Merge branch 'jk/stop-pack-objects-when-fetch-is-killed'

"git fetch" that is killed may leave a pack-objects process behind,
still computing to find a good compression, wasting cycles.  This
has been corrected.

* jk/stop-pack-objects-when-fetch-is-killed:
  upload-pack: kill pack-objects helper on signal or exit

upload-pack.c

@@ -321,6 +321,7 @@ static void create_pack_file(struct upload_pack_data *pack_data,
 	pack_objects.in = -1;
 	pack_objects.out = -1;
 	pack_objects.err = -1;
+	pack_objects.clean_on_exit = 1;
 
 	if (start_command(&pack_objects))
 		die("git upload-pack: unable to fork git-pack-objects");