use lumberjack for log rolling

This is very similar to the last PR, except I didn't change out the upstart config stuff... since the output redirect doesn't hurt anything, and we need the rest of the code to properly set permissions and owner on the logfile.
I'll just note you have a const "exit_panic" that is used later, it can be used here, too.
Though the later one is "exit_err" not "exit_panic" isn't it?
Mabye you changed the wrong one?