ceph.spec: install/uninstall init script

This was commented out almost years ago in commit 9baf5ef4 but it is not
clear to me that it was correct to do so.  In any case, we are not
installing the rc.d links for ceph, which means it does not start up after
a reboot.

Signed-off-by: Sage Weil <sage@inktank.com>