Fixes the usage of PowerVMFileTransferFailed class

If it fails in the process of "Calculate file size in multiples of 512
bytes", the exception.PowerVMFileTransferFailed message is illegal.
"KeyError: u'file_path'" is occurs when there is no argument.

Change-Id: I15a7467bbc103f683d82949dc0892210cd63c4b6
Closes-Bug: #1223198
Fix races in cells extension tests

A global was used for a cell list and tests would update this global and
fail depending on order run, etc.

Fixes bug 1235399

Change-Id: Ib06cfc89076e87ac3cfedd796687059862f20406
Merge "Fixes the usage of PowerVMFileTransferFailed class"