Don't specify pid file in rsync.conf.

Specifying it here causes a weird problem where init.d creates
the file and then rsync bails out, upset that the pid file
is already there.  Everything seems to work when I remove it
here.

Change-Id: I5e03809d2c4c981d11f75b4a55ef3b07466175f3
Merge "Don't specify pid file in rsync.conf." into production