cast status code to an int in move/copy celery task

 * For some reason the HTTPStatus.CREATED enum was not being converted
   to an integer status code when sending a response back from
   celery.  Perhaps it was being unpickled wrongly?  Dunno, but
   reverting for now to unbreak move/copy tasks.

waterbutler/server/api/v1/provider/movecopy.py

@@ -159,8 +159,8 @@ async def move_or_copy(self):
         self.dest_meta = metadata
 
         if created:
-            self.set_status(HTTPStatus.CREATED)
+            self.set_status(int(HTTPStatus.CREATED))
         else:
-            self.set_status(HTTPStatus.OK)
+            self.set_status(int(HTTPStatus.OK))
 
         self.write({'data': metadata.json_api_serialized(self.dest_resource)})