Preserve already configured options in openldap conf
    
    We should respect already configured options present in
    /etc/openldap/ldap.conf when generating our own configuration.
    
    With this patch, we only rewrite URI, BASE and TLS_CACERT options
    only if they are not configured. In the case they are, our suggested
    configuration is inserted as a comment.
    
    Also adds tab as a delimeter character in /etc/openldap/ldap.conf
    
    https://fedorahosted.org/freeipa/ticket/3582