Incorporate fetched packs in future object traversal

Immediately after fetching a pack, we should call reprepare_packed_git() to
make sure the objects in the pack are reachable. Otherwise, we will fail to
look up objects that are present only in the fetched pack.

Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-fetch-pack.c

@@ -820,5 +820,6 @@ struct ref *fetch_pack(struct fetch_pack_args *my_args,
 		}
 	}
 
+	reprepare_packed_git();
 	return ref_cpy;
 }