storage: fixing a double call of get_images_list
storage: fixing a double call of get_images_list

Using just
 result = cli.getImagesList(self._sdUUID)
instead of
 result = cli.getImagesList(cli.getImagesList(self._sdUUID))

It's iSCSI specific since getImagesList always fails on NFS
due to rhbz#1274622 but in that case scanning the directory
on the mount point is enough while on iSCSI we have to rely
just on getImagesList since before preparing the images we
don't have a link to the volumes.

Change-Id: I2baf5d24d794486b713fbafdea4049e0b885671f
Bug-Url: https://bugzilla.redhat.com/1297457
Signed-off-by: Simone Tiraboschi <cb03129c66ba4da7ba7044049d0f43907bf857bb@redhat.com>
oVirt/ovirt-hosted-engine-ha,oVirt/ovirt-hosted-engine-ha,oVirt/ovirt-hosted-engine-ha,oVirt/ovirt-hosted-engine-ha