Start dirsrv for kdcproxy upgrade
    
    The kdcproxy upgrade step in ipa-server-upgrade needs a running dirsrv
    instance. Under some circumstances the dirsrv isn't running. The patch
    rearranges some upgrade steps and starts DS before enable_kdcproxy().
    
    https://fedorahosted.org/freeipa/ticket/5113
    
    Reviewed-By: Martin Basti <mbasti@redhat.com>