when bucket is created for the first time, reference to it is not saved

Nobody has claimed this yet.

Which results in an error:

```
at GCETransport.initResumableUpload (/src/node_modules/ms-files-gce/lib/index.js:227:40)
at Files.initFileUpload (/src/lib/actions/upload.js:36:19)
at Files.tryCatcher (/src/node_modules/bluebird/js/release/util.js:11:23)
at Promise._settlePromiseFromHandler (/src/node_modules/bluebird/js/release/promise.js:489:31)
at Promise._settlePromise (/src/node_modules/bluebird/js/release/promise.js:546:18)
at Promise._settlePromise0 (/src/node_modules/bluebird/js/release/promise.js:591:10)
at Promise._settlePromises (/src/node_modules/bluebird/js/release/promise.js:674:18)
at Async._drainQueue (/src/node_modules/bluebird/js/release/async.js:125:16)
at Async._drainQueues (/src/node_modules/bluebird/js/release/async.js:135:10)
at Immediate.Async.drainQueues [as _onImmediate] (/src/node_modules/bluebird/js/release/async.js:16:14)
at processImmediate [as _immediateCallback] (timers.js:383:17)
```

Start by reproducing the first-time bucket creation flow and trace the failure from lib/actions/upload.js:36 into ms-files-gce/lib/index.js:227. Check how the newly created bucket reference is handled, then verify that a first upload completes without this error and that the reference is available afterward.

Written by the indexing model from the issue text.