CRM-18193 add default log_conn values for when interacting with mysql outside of...

CRM-18193 add default log_conn values for when interacting with mysql outside of CiviCRM.

In this instand @uniqueID will not be set. We had a go at setting it within the trigger but that was unreliable. Eventual decision was a string 'con_' to identify a system connection + a timestamp to hourly granularity + the connection id. Proposed further work is to specifically block the revert from the UI for these and add a higher permission or a 'yes I really really mean it' param to the revert api for these