Improve error messages in ipa-replica-manage.
    
    Correctly handle case where we bind using GSSAPI with an unauthorized user.
    
    Remove extraneous except clause. We now have handle for LDAP errors.
    
    Make it explicit in a few places what server we can't connect to.
    
    When the remote replica is down and we are forcing its removal, remove
    a duplicate entry from the list of servers to remove.
    
    https://fedorahosted.org/freeipa/ticket/2871