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>

patch-ids.c

@@ -116,6 +116,6 @@ struct patch_id *add_commit_patch_id(struct commit *commit,
 		return NULL;
 	}
 
-	hashmap_add(&ids->patches, key);
+	hashmap_add(&ids->patches, &key->ent);
 	return key;
 }