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>
diff --git a/builtin/fetch.c b/builtin/fetch.c
index b7d70ee..909dbde 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -278,7 +278,7 @@ static struct refname_hash_entry *refname_hash_add(struct hashmap *map,
 	FLEX_ALLOC_MEM(ent, refname, refname, len);
 	hashmap_entry_init(&ent->ent, strhash(refname));
 	oidcpy(&ent->oid, oid);
-	hashmap_add(map, ent);
+	hashmap_add(map, &ent->ent);
 	return ent;
 }