[r=axwalk],[bug=1300889] Disable --keyFile in mongo upstart config
We can't enable this yet, because shared-secret
isn't written until after Mongo is started. This
will change when EnsureMongoServer is landed.
(FWIW I did test this with local, and it worked.
I don't yet understand why - it shouldn't be any
different to cloud providers. I suspect there's
a race here with upstart restarting Mongo, and
the machine agnet writing the shared-secret.)
Fixes lp:1300889
https://codereview.appspot.com/83270045/