Error acquiring write lock while committing management transaction with bigtable backend

Hey,
I am using janusgraph with bigtable backend and am trying to create a property key. As soon as I commit this transaction using `management.commit()`, I get the following error:

```
org.janusgraph.core.JanusGraphException: Could not commit transaction due to exception during persistence
at org.janusgraph.graphdb.transaction.StandardJanusGraphTx.commit(StandardJanusGraphTx.java:1374)
at org.janusgraph.graphdb.database.management.ManagementSystem.commit(ManagementSystem.java:235)
at org.janusgraph.core.schema.JanusGraphManagement$commit$0.call(Unknown Source)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:117)
at groovysh_evaluate.run(groovysh_evaluate:3)
at org.codehaus.groovy.vmplugin.v7.IndyInterface.selectMethod(IndyInterface.java:232)
at org.codehaus.groovy.tools.shell.Interpreter.evaluate(Interpreter.groovy:70)
at org.codehaus.groovy.tools.shell.Groovysh.execute(Groovysh.groovy:190)
at org.apache.tinkerpop.gremlin.console.GremlinGroovysh.super$3$execute(GremlinGroovysh.groovy)
at sun.reflect.GeneratedMethodAccessor14.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1215)
at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.invokeMethodOnSuperN(ScriptBytecodeAdapter.java:132)
at org.apache.tinkerpop.gremlin.console.GremlinGroovysh.execute(GremlinGroovysh.groovy:72)
at org.codehaus.groovy.tools.shell.Shell.leftShift(Shell.groovy:122)
at org.codehaus.groovy.tools.shell.ShellRunner.work(ShellRunner.groovy:95)
at org.codehaus.groovy.tools.shell.InteractiveShellRunner.super$2$work(InteractiveShellRunner.groovy)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1215)
at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.invokeMethodOnSuperN(ScriptBytecodeAdapter.java:132)
at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.invokeMethodOnSuper0(ScriptBytecodeAdapter.java:152)
at org.codehaus.groovy.tools.shell.InteractiveShellRunner.work(InteractiveShellRunner.groovy:124)
at org.codehaus.groovy.tools.shell.ShellRunner.run(ShellRunner.groovy:59)
at org.codehaus.groovy.tools.shell.InteractiveShellRunner.super$2$run(InteractiveShellRunner.groovy)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1215)
at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.invokeMethodOnSuperN(ScriptBytecodeAdapter.java:132)
at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.invokeMethodOnSuper0(ScriptBytecodeAdapter.java:152)
at org.codehaus.groovy.tools.shell.InteractiveShellRunner.run(InteractiveShellRunner.groovy:83)
at org.codehaus.groovy.vmplugin.v7.IndyInterface.selectMethod(IndyInterface.java:232)
at org.apache.tinkerpop.gremlin.console.Console.(Console.groovy:152)
at org.codehaus.groovy.vmplugin.v7.IndyInterface.selectMethod(IndyInterface.java:232)
at org.apache.tinkerpop.gremlin.console.Console.main(Console.groovy:455)
Caused by: org.janusgraph.core.JanusGraphException: Unexpected exception
at org.janusgraph.graphdb.database.StandardJanusGraph.commit(StandardJanusGraph.java:798)
at org.janusgraph.graphdb.transaction.StandardJanusGraphTx.commit(StandardJanusGraphTx.java:1363)
... 47 more
Caused by: org.janusgraph.diskstorage.locking.TemporaryLockingException: Temporary locking failure
at org.janusgraph.diskstorage.locking.AbstractLocker.writeLock(AbstractLocker.java:309)
at org.janusgraph.diskstorage.locking.consistentkey.ExpectedValueCheckingStore.acquireLock(ExpectedValueCheckingStore.java:103)
at org.janusgraph.diskstorage.keycolumnvalue.KCVSProxy.acquireLock(KCVSProxy.java:52)
at org.janusgraph.diskstorage.BackendTransaction.acquireIndexLock(BackendTransaction.java:255)
at org.janusgraph.graphdb.database.StandardJanusGraph.prepareCommit(StandardJanusGraph.java:565)
at org.janusgraph.graphdb.database.StandardJanusGraph.commit(StandardJanusGraph.java:694)
... 48 more
Caused by: org.janusgraph.diskstorage.TemporaryBackendException: Lock write retry count exceeded
at org.janusgraph.diskstorage.locking.consistentkey.ConsistentKeyLocker.writeSingleLock(ConsistentKeyLocker.java:339)
at org.janusgraph.diskstorage.locking.consistentkey.ConsistentKeyLocker.writeSingleLock(ConsistentKeyLocker.java:123)
at org.janusgraph.diskstorage.locking.AbstractLocker.writeLock(AbstractLocker.java:304)
... 53 more
```

**How to reproduce**

To reproduce this, just get the `janusgraph` up and running with `bigtable` storage backend and do the following within gremlin shell:

```
graph = JanusGraphFactory.open('conf/yourconf.properties')
management = graph.openManagement()
uid = management.makePropertyKey("uid").dataType(String.class).make()
management.commit()
```

**Update: Version & Config Information**

- Janusgraph: janusgraph-0.1.0-hadoop2
- Backend: Bigtable (`bigtable-hbase-1.x-hadoop-1.0.0-pre2.jar`, `netty-tcnative-boringssl-static-1.1.33.Fork26.jar`)
- OS: Mac OSX Sierra 10.12.2

Configuration is as follows:

```
storage.backend=hbase

## Google cloud BIGTABLE configuration options
storage.hbase.ext.hbase.client.connection.impl=com.google.cloud.bigtable.hbase1_x.BigtableConnection
storage.hbase.ext.google.bigtable.project.id=project-id
storage.hbase.ext.google.bigtable.instance.id=instance-id

storage.hostname=localhost
cache.db-cache = true
cache.db-cache-clean-wait = 20
cache.db-cache-time = 180000
cache.db-cache-size = 0.5
```

Start by running the supplied Gremlin reproduction with the listed Bigtable configuration. Trace the failure through AbstractLocker.writeLock, ConsistentKeyLocker.writeSingleLock, and BackendTransaction.acquireIndexLock, then compare the locking behavior for this backend. Done means the management transaction creates the property key and commits without the temporary locking failure.

Written by the indexing model from the issue text.