Merge branch 'jt/upload-pack-error-report' into maint

"git upload-pack", which is a counter-part of "git fetch", did not
report a request for a ref that was not advertised as invalid.
This is generally not a problem (because "git fetch" will stop
before making such a request), but is the right thing to do.

* jt/upload-pack-error-report:
  upload-pack: report "not our ref" to client

upload-pack.c

@@ -822,9 +822,13 @@ static void receive_needs(void)
 			use_include_tag = 1;
 
 		o = parse_object(sha1_buf);
-		if (!o)
+		if (!o) {
+			packet_write_fmt(1,
+					 "ERR upload-pack: not our ref %s",
+					 sha1_to_hex(sha1_buf));
 			die("git upload-pack: not our ref %s",
 			    sha1_to_hex(sha1_buf));
+		}
 		if (!(o->flags & WANTED)) {
 			o->flags |= WANTED;
 			if (!((allow_unadvertised_object_request & ALLOW_ANY_SHA1) == ALLOW_ANY_SHA1