ktest: Only need to save .config when doing mrproper

Only save the .config file if we're doing mrproper

Signed-off-by: Andrew Jones <drjones@redhat.com>
Link: http://lkml.kernel.org/r/1313155932-20092-3-git-send-email-drjones@redhat.com


Signed-off-by: Steven Rostedt <rostedt@goodmis.org>