GFS2: Fix uninitialised error value in previous patch

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index ae7d205..3c4039d 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -763,7 +763,7 @@
 	int metadata;
 	unsigned int revokes = 0;
 	int x;
-	int error;
+	int error = 0;
 
 	if (!*top)
 		sm->sm_first = 0;