lio backstore block vs iblock

Hi,

I'm not sure if this is a problem with incompatible changes between targetcli versions, but I always got a Traceback
`ERROR: Traceback (most recent call last): File "/usr/bin/targetcli", line 89, in main() File "/usr/bin/targetcli", line 78, in main shell.run_cmdline(" ".join(sys.argv[1:])) File "/usr/lib/python2.7/dist-packages/configshell/shell.py", line 934, in run_cmdline self._execute_command(path, command, pparams, kparams) File "/usr/lib/python2.7/dist-packages/configshell/shell.py", line 899, in _execute_command self.log.error(msg) File "/usr/lib/python2.7/dist-packages/configshell/log.py", line 159, in error self._log('error', msg) File "/usr/lib/python2.7/dist-packages/configshell/log.py", line 112, in _log self.con.display(msg) File "/usr/lib/python2.7/dist-packages/configshell/console.py", line 153, in display self.raw_write(text) File "/usr/lib/python2.7/dist-packages/configshell/console.py", line 141, in raw_write self._stdout.write(text) TypeError: expected a string or other character buffer object`

and after some debugging found out the problem is `targetcli /backstores/block create` vs `targetcli /backstores/iblock create`, and after applying the following diff everything worked fine:

```
--- iSCSILogicalUnit.orig 2016-07-11 15:43:33.324955524 +0000
+++ iSCSILogicalUnit 2016-07-11 15:43:40.884842482 +0000
@@ -362,11 +362,11 @@
lio-t)
# For lio, we first have to create a target device, then
# add it to the Target Portal Group as an LU.
- ocf_run targetcli /backstores/block create name=${OCF_RESOURCE_INSTANCE} dev=${OCF_RESKEY_path} || exit $OCF_ERR_GENERIC
+ ocf_run targetcli /backstores/iblock create name=${OCF_RESOURCE_INSTANCE} dev=${OCF_RESKEY_path} || exit $OCF_ERR_GENERIC
if [ -n "${OCF_RESKEY_scsi_sn}" ]; then
echo ${OCF_RESKEY_scsi_sn} > /sys/kernel/config/target/core/iblock_${OCF_RESKEY_lio_iblock}/${OCF_RESOURCE_INSTANCE}/wwn/vpd_unit_serial
fi
- ocf_run targetcli /iscsi/${OCF_RESKEY_target_iqn}/tpg1/luns create /backstores/block/${OCF_RESOURCE_INSTANCE} ${OCF_RESKEY_lun} || exit $OCF_ERR_GENERIC
+ ocf_run targetcli /iscsi/${OCF_RESKEY_target_iqn}/tpg1/luns create /backstores/iblock/${OCF_RESOURCE_INSTANCE} ${OCF_RESKEY_lun} || exit $OCF_ERR_GENERIC

if [ -n "${OCF_RESKEY_allowed_initiators}" ]; then
for initiator in ${OCF_RESKEY_allowed_initiators}; do
@@ -444,7 +444,7 @@
# delete the backstore, then something is seriously
# wrong and we need to fail the stop operation
# (potentially causing fencing)
- ocf_run targetcli /backstores/block delete ${OCF_RESOURCE_INSTANCE} || exit $OCF_ERR_GENERIC
+ ocf_run targetcli /backstores/iblock delete ${OCF_RESOURCE_INSTANCE} || exit $OCF_ERR_GENERIC
;;
esac
```

versions:

```
root@hase01b:~# uname -a
Linux hase01b 4.6.0-1-amd64 #1 SMP Debian 4.6.2-2 (2016-06-25) x86_64 GNU/Linux
root@hase01b:~# targetcli version
Using configshell version 1.6.1~g020d540
Using rtslib version 3.0.pre4.1~g1b33ceb
Using targetcli version 3.0.pre4.1~ga55d018
```

Locate the iSCSILogicalUnit resource agent and inspect the lio-t branch around the targetcli backstore create, LUN create, and delete commands. Compare those commands with the reported targetcli versions and verify that the iblock paths work consistently; done means the agent no longer triggers the reported traceback during create or cleanup.

Written by the indexing model from the issue text.