commit: add repository argument to lookup_commit_reference

Add a repository argument to allow callers of lookup_commit_reference
to be more specific about which repository to handle. 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: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/commit.c b/commit.c
index 756d557..5e50a07 100644
--- a/commit.c
+++ b/commit.c
@@ -35,14 +35,14 @@ struct commit *lookup_commit_reference_gently_the_repository(
 	return object_as_type(the_repository, obj, OBJ_COMMIT, quiet);
 }
 
-struct commit *lookup_commit_reference(const struct object_id *oid)
+struct commit *lookup_commit_reference_the_repository(const struct object_id *oid)
 {
 	return lookup_commit_reference_gently(the_repository, oid, 0);
 }
 
 struct commit *lookup_commit_or_die(const struct object_id *oid, const char *ref_name)
 {
-	struct commit *c = lookup_commit_reference(oid);
+	struct commit *c = lookup_commit_reference(the_repository, oid);
 	if (!c)
 		die(_("could not parse %s"), ref_name);
 	if (oidcmp(oid, &c->object.oid)) {
@@ -68,7 +68,7 @@ struct commit *lookup_commit_reference_by_name(const char *name)
 
 	if (get_oid_committish(name, &oid))
 		return NULL;
-	commit = lookup_commit_reference(&oid);
+	commit = lookup_commit_reference(the_repository, &oid);
 	if (parse_commit(commit))
 		return NULL;
 	return commit;