hashmap_remove takes "const struct hashmap_entry *"

This is less error-prone than "const 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>

hashmap.c

@@ -218,7 +218,8 @@ void hashmap_add(struct hashmap *map, struct hashmap_entry *entry)
 	}
 }
 
-void *hashmap_remove(struct hashmap *map, const void *key, const void *keydata)
+void *hashmap_remove(struct hashmap *map, const struct hashmap_entry *key,
+		const void *keydata)
 {
 	struct hashmap_entry *old;
 	struct hashmap_entry **e = find_entry_ptr(map, key, keydata);