logrotate.conf: fixes for systemd

logrotate.conf: fixes for systemd

Before this patch, the command 'logrotate -f /etc/logrotate.d/ceph'
was generating an error "Failed to reload ceph.target: Job type reload is not
applicable for unit ceph.target".

Before we issue systemctl reload, check that there is at least
one active ceph-* service. (The hyphen is significant.)

Since we use grep, make the grep package a dependency.

http://tracker.ceph.com/issues/12173 Fixes: #12173

Signed-off-by: Tim Serong <tserong@suse.com>
Signed-off-by: Lars Marowsky-Bree <lmb@suse.com>
Signed-off-by: Nathan Cutler <ncutler@suse.com>