Trn 135 bug fix

    Fixed bug in TRN-135 commit
    
    gocql's MapScan is doing strange things. The argument to MapScan is
    advertised to be an output paramanter. But if the map already has
    elements, it appears that MapScan flags an error (which AFAICT
    it should not).

This issue was reported by Dan on the JIRA ticket https://jira2.iparadigms.com/browse/TRN-135.