commit: add repository argument to lookup_commit_reference_gently

Add a repository argument to allow callers of
lookup_commit_reference_gently 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/builtin/fetch.c b/builtin/fetch.c
index 83f36d7..f5d960b 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -684,8 +684,10 @@ static int update_local_ref(struct ref *ref,
 		return r;
 	}
 
-	current = lookup_commit_reference_gently(&ref->old_oid, 1);
-	updated = lookup_commit_reference_gently(&ref->new_oid, 1);
+	current = lookup_commit_reference_gently(the_repository,
+						 &ref->old_oid, 1);
+	updated = lookup_commit_reference_gently(the_repository,
+						 &ref->new_oid, 1);
 	if (!current || !updated) {
 		const char *msg;
 		const char *what;
@@ -818,7 +820,8 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 				continue;
 			}
 
-			commit = lookup_commit_reference_gently(&rm->old_oid,
+			commit = lookup_commit_reference_gently(the_repository,
+								&rm->old_oid,
 								1);
 			if (!commit)
 				rm->fetch_head_status = FETCH_HEAD_NOT_FOR_MERGE;