xfs: fix uninitialized variable in _reflink_convert_cow

Fix an uninitialize variable.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_reflink.c

@@ -362,7 +362,7 @@ xfs_reflink_convert_cow(
 	xfs_fileoff_t		end_fsb = XFS_B_TO_FSB(mp, offset + count);
 	xfs_extnum_t		idx;
 	bool			found;
-	int			error;
+	int			error = 0;
 
 	xfs_ilock(ip, XFS_ILOCK_EXCL);