Fix: use DS socket check only for upgrade
    
    To detect if DS server is running, use the slapd socket for upgrade, and the LDAP port
    for installation.
    
    Without enabled LDAPi socket checking doesnt work.
    
    https://fedorahosted.org/freeipa/ticket/4904
    
    Reviewed-By: Fraser Tweedale <ftweedal@redhat.com>