Mark getImageDomainsList() as deprecated.

getImageDomainsList needs to be connected to the pool and ignores
every non responding domain. Therefore the result can be wrong and
misleading.
This function should be replaced by getImagesList call.

Change-Id: Icf7c9dd7cd122862c50f452a0f4587a64e5c4b6f
Signed-off-by: Eduardo <ewarszaw@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/12591
Tested-by: Daniel Paikov <paikov@gmail.com>
Reviewed-by: Yeela Kaplan <ykaplan@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>