fix broken test

Author: peff

t/t1400-update-ref.sh

@@ -2189,7 +2189,7 @@ do
 			git update-ref refs/heads/ref2 $head &&
 
 			format_command $type "update refs/heads/ref1" "$old_head" "$head" >stdin &&
-			format_command $type "symref-update refs/heads/ref2" "$old_head" "ref" "refs/heads/nonexistent" >>stdin &&
+			format_command $type "symref-update refs/heads/ref2" "refs/heads/new" "ref" "refs/heads/nonexistent" >>stdin &&
 			git update-ref $type --no-deref --stdin --batch-updates <stdin >stdout &&
 			echo $old_head >expect &&
 			git rev-parse refs/heads/ref1 >actual &&