Retry retrieving ldap principals when setting up replication.
    
    We've seen on a few occassions where one side or the other is missing
    the ldap principal. This causes replication to fail when trying to
    convert to using GSSAPI. If this happens force a synchronization again
    and try the retrieval again, up to 10 times.
    
    This should also make the error report clearer if even after the retries
    one of the principals doesn't exist.
    
    https://fedorahosted.org/freeipa/ticket/2737