[WORKER] Change gearman poll default to 1

Because of the way python-gearman currently works, we can get a long
delay (up to whatever the current poll timeout is set to) when that
module does an epoll.poll() call that will block for that long. When
a NOOP is received, the socket is only recognized as writable (for the
GRAB_JOB request) when there is buffered output so it isn't until the
NEXT poll() that it actually grabs the job and processes the result.

Change-Id: Ib2c488355453aeea6c0bf4f3cf5ccc376c33395a
Merge "[WORKER] Change gearman poll default to 1"