ba9d5c0 PAM: only allow missing user name for certificate authentication

2 files Authored by sbose 6 years ago, Committed by lslebodn 6 years ago,
    PAM: only allow missing user name for certificate authentication
    
    Resolves:
    https://fedorahosted.org/sssd/ticket/2811
    
    Reviewed-by: Lukáš Slebodník <lslebodn@redhat.com>
    (cherry picked from commit 2e76b32e74abedb23665808bacc73cafd1097c37)