TT#116900 Use multidomain when deleting a registration

* deleting a registration would fail when the domain
            of the registrations would not exist due to the
            fact that multidomain is not enabled

Change-Id: If512c0c9ce6c8f7a72deaa5b6a8ebe6737404f2a
(cherry picked from commit a9817e52d8)

lib/NGCP/Panel/Controller/Subscriber.pm

@@ -4353,7 +4353,7 @@ sub delete_registered :Chained('registered') :PathPart('delete') :Args(0) {
 
     try {
         my $reg = $c->stash->{registered} // die "No registration data";
-        my $aor = $reg->username . '@' . $reg->domain;
+        my $aor = $reg->username . ($c->config->{features}->{multidomain} ? '@' . $reg->domain : '');
         NGCP::Panel::Utils::Kamailio::delete_location_contact($c, $aor, $reg->contact);
     } catch($e) {
         NGCP::Panel::Utils::Message::error(