core: fix mock in MoveOrCopyDiskCommand

In mockGetVmsListForDisk() the vm1 was added twice to vmList.

Change-Id: Id3f2991d89c37c8c6139f810ca5eebccea89d96f
Signed-off-by: Vered Volansky <vvolansk@redhat.com>
core: MoveOrCopyDiskCommand space verification

This is a part of a series of patches intended to fix storage space
allocation validation throughout the system (see bz).
Added hasSpaceForClonedDisk(s) in StorageDomainValidator.
Applied use in MoveOrCopyDiskCommand (former use is buggy).

Change-Id: I951aeb531cb7ff7aaf3f1d50fc55100b6a806059
Bug-url: https://bugzilla.redhat.com/960934
Signed-off-by: Vered Volansky <vvolansk@redhat.com>