hashmap_add takes "struct hashmap_entry *"

This is less error-prone than "void *" as the compiler now
detects invalid types being passed.

Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

attr.c

@@ -122,7 +122,7 @@ static void attr_hashmap_add(struct attr_hashmap *map,
 	e->keylen = keylen;
 	e->value = value;
 
-	hashmap_add(&map->map, e);
+	hashmap_add(&map->map, &e->ent);
 }
 
 struct all_attrs_item {