[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>
diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index d0db881..c186857 100644
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -279,7 +279,7 @@
 		(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;