Use new CLI options in certinstall tests
    
    The --pin and --dirman-password options simplified ipa-certinstall
    usage. Use them in tests.
    
    Also add tests for the old way of calling the command.
    
    https://fedorahosted.org/freeipa/ticket/3869
    http://www.freeipa.org/page/V3/ipa-server-certinstall_CLI_cleanup