Update waitcondition API to use signal RPC interface

Update the call to the engine to use resource_signal instead
of metadata_update, since they do basically the same thing
and it would be good to converge on one interface for resource
signalling.

Change-Id: I1385f9f4539eeb7907370e31af5ea2f86870cbe9
blueprint: native-waitcondition

heat/api/cfn/v1/__init__.py

@@ -72,7 +72,7 @@ class API(wsgi.Router):
         signal_controller = signal.create_resource(conf)
         mapper.connect('/waitcondition/{arn:.*}',
                        controller=signal_controller,
-                       action='update_waitcondition',
+                       action='signal',
                        conditions=dict(method=['PUT']))
         mapper.connect('/signal/{arn:.*}',
                        controller=signal_controller,

heat/api/cfn/v1/signal.py

@@ -22,20 +22,6 @@ class SignalController(object):
         self.options = options
         self.rpc_client = rpc_client.EngineClient()
 
-    def update_waitcondition(self, req, body, arn):
-        con = req.context
-        identity = identifier.ResourceIdentifier.from_arn(arn)
-        try:
-            md = self.rpc_client.metadata_update(
-                con,
-                stack_identity=dict(identity.stack()),
-                resource_name=identity.resource_name,
-                metadata=body)
-        except Exception as ex:
-            return exception.map_remote_error(ex)
-
-        return {'resource': identity.resource_name, 'metadata': md}
-
     def signal(self, req, arn, body=None):
         con = req.context
         identity = identifier.ResourceIdentifier.from_arn(arn)