fix bug 654. First  vdu's placement-groups does not work

Change-Id: Idc935fa13ab6b8e138472de4ebc932810a5e9c5b
Signed-off-by: tierno <alfonso.tiernosepulveda@telefonica.com>
diff --git a/osm_ro/nfvo.py b/osm_ro/nfvo.py
index 281b8f9..f65f08f 100644
--- a/osm_ro/nfvo.py
+++ b/osm_ro/nfvo.py
@@ -1291,8 +1291,7 @@
                                             "'member-vdus':'{vdu}'. Reference to a non-existing vdu".format(
                                                 vnf=vnfd_id, pg=pg_name, vdu=vdu_id),
                                             httperrors.Bad_Request)
-                    if vdu_id2db_table_index[vdu_id]:
-                        db_vms[vdu_id2db_table_index[vdu_id]]["availability_zone"] = pg_name
+                    db_vms[vdu_id2db_table_index[vdu_id]]["availability_zone"] = pg_name
                     # TODO consider the case of isolation and not colocation
                     # if pg.get("strategy") == "ISOLATION":