GFS2: Move rg_free from gfs2_rgrpd_host to gfs2_rgrpd

The second of three fields which need to move, in order
to remove the struct gfs2_rgrpd_host.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --cc fs/gfs2/incore.h
Simple merge

diff --cc fs/gfs2/rgrp.c
Simple merge

diff --cc fs/gfs2/super.c
Simple merge