#1701 [HHQ-2167] Script plugin does not return an availability met

[Hyperic Team]

http://jira.hyperic.com/browse/HHQ-2167


If a script times out the execution time is properly returned but no availability metric is sent. This results in the UI showing grey and has the unwanted side effect of not being able to alert of this condition since no metric is coming in. (the backfiller will no backfill unknown data points if the platform is reporting)