Ticket #291 - cannot use & in a sasl map search filter
    
    Bug Description:  The '&' was getting replaced in slapi_re_subs() when processing
                      search filter mappings.
    
    Fix Description:  Created extension of slapi_re_subs() to pass in filter flag.
                      It checks to see if the '&' is a separator of filter components
                      or not, by looking for "(&(".
    
    https://fedorahosted.org/389/ticket/291