rescue in resque:stop task in order to allow for task chain execution to...

If the pid file contains a defunct pid, the kill command exits with a failure code, and the task resque:stop fails.  If there is a chain of tasks, they all stop.  I think that this error should be non-fatal, so this is my attempt to allow for some continuation.  I'm not sure of maybe stop_command method might need a to change the && to something else, and ensure that rm -f $f runs anyway.
Thanks for making this gem