API: Error handling fixes

* Hide DELETED LBs
* Make sure DELETED LBs and devices don't show in anything
* Improve error handling for gearman
* Add statusDescription field to 'status' command
* Fix some response codes (WSME ones still off)

Change-Id: I45b78f29ab1e0d2f3e9aa8c936ad1518dbe2179a
Merge "API: Error handling fixes"