Don't post shutdown to master if agent_id unknown
Do not retry announcing while shutting down
close_log is called with a uuid, not a process
Call stop on the actual jobtype, not a copy of it
Ignore failed processes when removing jobtypes.

Failed processes are still stopped processes. If we wait for those to
disappear, we will wait forever.
Merge pull request #119 from guidow/agent_shutdown_fixes

Agent shutdown fixes