Fix powervm driver resize instance error

During a resize operation in powervm, the logical volume
of the instance will be copied and compressed to a file.
Current logic decompresses it twice before copying this file
to a new volume which will cause the new instance to not
boot properly.

Fixes bug #1169848

Change-Id: I91f536919511aafbf7dbe14abbee48dbceb189b2
(cherry picked from commit 5643bd5d9bf17335e109d4b2d93e161f4d12c6f9)
Merge "Fix powervm driver resize instance error" into stable/grizzly