schema-transfomer: clean stale route-target properly

When RouteTargets are reinitialized, the stale route targets (route
targets which doesn't have logical router backref or routing instance
back ref) are getting removed. But its not removed properly. Route
target remains on cls.__dict. Call the 'delete_vnc_obj' method which
cleans the route target properly.

Change-Id: Ib7583ef8560091d530d3f3ec4cccbb996d6e6e32
Closes-Bug: #1808518

src/config/schema-transformer/config_db.py

@@ -1395,7 +1395,7 @@ def reinit(cls):
                         obj.get_logical_router_back_refs()):
                     cls.locate(obj.get_fq_name_str(), obj)
                 else:
-                    cls._vnc_lib.route_target_delete(id=obj.uuid)
+                    cls.delete_vnc_obj(obj.get_fq_name_str())
             except Exception as e:
                 cls._logger.error("Error in reinit for %s %s: %s" % (
                     cls.obj_type, obj.get_fq_name_str(), str(e)))