4ee426a server install: do not prompt for cert file PIN repeatedly

Authored and Committed by jcholast 7 years ago
    server install: do not prompt for cert file PIN repeatedly
    
    Prompt for PIN only once in interactive mode.
    
    This fixes ipa-server-install, ipa-server-certinstall and
    ipa-replica-prepare prompting over and over when the PIN is empty.
    
    https://fedorahosted.org/freeipa/ticket/6032
    
    Reviewed-By: Pavel Vomacka <pvomacka@redhat.com>