ipa-client-install: Always pass hostname to the ipa-join
    
    The ipa-client-install script and ipa-join use different methods
    of resolving the hostname, the former uses gethostbyaddr() call,
    while the latter reads the "uinfo.nodename".
    
    This can result ipa-client-install failures in case of broken PTR
    records.
    
    https://fedorahosted.org/freeipa/ticket/4027