VMware: Handle exceptions raised by image update

Exceptions raised by glance image update are not handled while writing
to image. This results in volume being stuck in uploading state for
a long time even after image transfer failure. This patch fixes the
exception handling.

Change-Id: I7651c96968caa49c5421d68ee4dbe9e55f7f53b1
Closes-Bug: #1357239
Partial-Bug: #1269345
Merge "VMware: Handle exceptions raised by image update"