[WIP] Ems refresh status

Capture the status of an EMS Refresh (success or failure).

Currently captures the status for Openstack.  Need to look at adding this either the refresher super class or to each individual provider's refresher.
I was trying to help answer the question:

> "Seeing as though there's a failed refresh, when was the last successful refresh?"

It's possible that this is not important information to capture.