Make replica install more robust
    
    Under certain circumstances, replica installation may fail in
    "enable GSSAPI for replication" step when it cannot sync LDAP service
    principals. There is often not much we can do as Directory Server
    may be in an unrecoverable state but we should at least wait longer
    before we give up.
    
    A function checking replication status was also fixed to give more
    accurate results by properly comparing start/end time of the
    replication process and returning an error message to calling
    function. This error message is then returned to user if do not
    manage to get the LDAP service principals to give him a pointer
    to the actual issue.
    
    https://fedorahosted.org/freeipa/ticket/2950