xfs: fix uninitialized error variables

smatch complained about some uninitialized error returns, so fix those.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>

fs/xfs/libxfs/xfs_sb.c

@@ -877,7 +877,7 @@ xfs_initialize_perag_data(
 	uint64_t	bfreelst = 0;
 	uint64_t	btree = 0;
 	uint64_t	fdblocks;
-	int		error;
+	int		error = 0;
 
 	for (index = 0; index < agcount; index++) {
 		/*

fs/xfs/xfs_reflink.c

@@ -261,7 +261,7 @@ xfs_reflink_convert_cow_locked(
 	struct xfs_bmbt_irec	got;
 	struct xfs_btree_cur	*dummy_cur = NULL;
 	int			dummy_logflags;
-	int			error;
+	int			error = 0;
 
 	if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &got))
 		return 0;