engine: sort domain list query results

Changed the domain list query results to be sorted alphabetically, with
the special case of "internal" always appearing at the bottom.

Change-Id: Ia7e9f80b47a5b65924d7f78d7f658cf5db478ed1
Bug-Url: https://bugzilla.redhat.com/785555
Signed-off-by: Greg Sheremeta <gshereme@redhat.com>