Preserve pam-config files
    
    377a4c09aac121ae071b13f664899521e4cb8862 was implemented to
    keep the pam-config package installed - keep the files owned by
    the package as well to avoid them being replaced and removed again
    with updates.
    
    Signed-off-by: Georg Pfuetzenreuter <mail@georg-pfuetzenreuter.net>