Fix fix getDomUuidFromVolumePath()

Change-Id: I648e6a3f4e877c8f2471e82d7064c3e5a021d4d1
Bug-Url: http://bugzilla.redhat.com/1017735
Signed-off-by: Eduardo <ewarszaw@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/20783
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Tested-by: Dan Kenigsberg <danken@redhat.com>