[GFS2] fix locking mistake

This patch fixes a locking mistake in the quota code, we do a mutex_lock instead
of a mutex_unlock.
Signed-off-by: Josef Whiter <jwhiter@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/quota.c

@@ -279,7 +279,7 @@ static int bh_get(struct gfs2_quota_data *qd)
 		(bh->b_data + sizeof(struct gfs2_meta_header) +
 		 offset * sizeof(struct gfs2_quota_change));
 
-	mutex_lock(&sdp->sd_quota_mutex);
+	mutex_unlock(&sdp->sd_quota_mutex);
 
 	return 0;