diff -up yum-3.4.3/completion-helper.py.old yum-3.4.3/completion-helper.py
--- yum-3.4.3/completion-helper.py.old	2012-08-22 17:00:47.444104234 +0200
+++ yum-3.4.3/completion-helper.py	2012-08-22 17:00:57.954647525 +0200
@@ -70,6 +70,7 @@ def get_pattern(extcmds):
 
 def main(args):
     base = cli.YumBaseCli()
+    base.setCacheDir = lambda *x: True # use the system cachedir
     base.yum_cli_commands.clear()
     base.registerCommand(GroupsCompletionCommand())
     base.registerCommand(ListCompletionCommand())