Moved timestamp back into _persist_metadata.  Switched to previously used format #1108
Moved timestamp back into _persist_metadata.  Switched to previously used format #1108

RasaHQ/rasa_nlu,RasaHQ/rasa_core,RasaHQ/rasa_nlu,RasaHQ/rasa_core,RasaHQ/rasa_nlu,RasaHQ/rasa_core