Remove ceph-radosgw.target when switching to containerize daemons

Remove ceph-radosgw.target when switching to containerize daemons

The task "remove old systemd unit file" under "switching from
non-containerized to containerized ceph rgw" only removes
the ceph-radosgw@.service file. The task should also remove
the ceph-radosgw.target file, like the "remove old systemd unit
files" tasks for the mons, mgrs, osds, etc, in order to clean up
all of the unused systemd unit files.

Signed-off-by: Kevin Coakley <kcoakley@sdsc.edu>