tag: add repository argument to deref_tag

Add a repository argument to allow the callers of deref_tag
to be more specific about which repository to act on. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/commit.c b/commit.c
index 9e2899b..aa5557d 100644
--- a/commit.c
+++ b/commit.c
@@ -27,7 +27,8 @@ const char *commit_type = "commit";
 struct commit *lookup_commit_reference_gently_the_repository(
 		const struct object_id *oid, int quiet)
 {
-	struct object *obj = deref_tag(parse_object(the_repository, oid),
+	struct object *obj = deref_tag(the_repository,
+				       parse_object(the_repository, oid),
 				       NULL, 0);
 
 	if (!obj)