Add logging to track down OOM

The WMF job runners have been OOM'ing fairly recently lately.
Watching the memory for the jobrunners we can see they don't grow
their memory over time like a leak, instead they sit at 80M for
some time until quickly growing to >300M and dieing.  The logs
all point to line 666, which issues commands to redis.  I'm not
sure whats going on yet, but I think if we log the commands so we
know what it did just before OOM we can figure that out.

Change-Id: Ie927b49b0b21a4478e7ea8c207d1e65b9c63c729