Merge branch 'db/learn-HEAD'

* db/learn-HEAD:
  Make ls-remote http://... list HEAD, like for git://...
  Make walker.fetch_ref() take a struct ref.

cache.h

@@ -635,6 +635,7 @@ struct ref {
 	struct ref *next;
 	unsigned char old_sha1[20];
 	unsigned char new_sha1[20];
+	char *symref;
 	unsigned int force:1,
 		merge:1,
 		nonfastforward:1,