init-ceph: make ulimit -n be part of daemon command

ulimit -n from 'max open files' was being set only on the machine
running /etc/init.d/ceph.  It needs to be added to the commands to
start the daemons, and run both locally and remotely.

Verified by examining /proc/<pid>/limits on local and remote hosts

Fixes: #3900
Signed-off-by: Dan Mick <dan.mick@inktank.com>
Reviewed-by: Loïc Dachary <loic@dachary.org>
Reviewed-by: Gary Lowell <gary.lowell@inktank.com>