Check vm's disk state while waiting for image creation finish

When try with RHEV 3.1, image creation doesn't lock the vms, so
we need to check disk state while waiting for the image to be
created.

Bug: 906214
Change-Id: Ia4118018e3b142064f1632be03c726fbe6f00722
Merge "Check vm's disk state while waiting for image creation finish" into develop