This fixes things like:

  portal_catalog(source_reference={'query':'foo OR bar', 'key':'KeywordKey'})

or:

  portal_catalog(query=AutoQuery(source_reference='foo OR bar', key='KeywordKey'))

So we get:

  (`...`.`reference` LIKE '%foo%' OR `...`.`reference` LIKE '%bar%')

instead of:

  `...`.`reference` IN ('{\'query\': \'foo\', \'key\': \'KeywordKey\'}',
                        '{\'query\': \'bar\', \'key\': \'KeywordKey\'}')