[GFS2] Reduce number of gfs2_scand processes to one

We only need a single gfs2_scand process rather than the one
per filesystem which we had previously. As a result the parameter
determining the frequency of gfs2_scand runs becomes a module
parameter rather than a mount parameter as it was before.

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

fs/gfs2/ops_super.c

@@ -92,7 +92,6 @@ static void gfs2_put_super(struct super_block *sb)
 	kthread_stop(sdp->sd_recoverd_process);
 	while (sdp->sd_glockd_num--)
 		kthread_stop(sdp->sd_glockd_process[sdp->sd_glockd_num]);
-	kthread_stop(sdp->sd_scand_process);
 
 	if (!(sb->s_flags & MS_RDONLY)) {
 		error = gfs2_make_fs_ro(sdp);