[CDB-3639] Test -1 in sequel connection validator
[CDB-3639] Test -1 in sequel connection validator

UCL-ShippingGroup/cartodb-1,raquel-ucl/cartodb,nyimbi/cartodb,DigitalCoder/cartodb,future-analytics/cartodb,DigitalCoder/cartodb,UCL-ShippingGroup/cartodb-1,codeandtheory/cartodb,codeandtheory/cartodb,DigitalCoder/cartodb,bloomberg/cartodb,UCL-ShippingGroup/cartodb-1,CartoDB/cartodb,bloomberg/cartodb,thorncp/cartodb,thorncp/cartodb,DigitalCoder/cartodb,UCL-ShippingGroup/cartodb-1,splashblot/dronedb,nuxcode/cartodb,thorncp/cartodb,future-analytics/cartodb,nyimbi/cartodb,nuxcode/cartodb,splashblot/dronedb,nyimbi/cartodb,thorncp/cartodb,dbirchak/cartodb,nyimbi/cartodb,splashblot/dronedb,future-analytics/cartodb,CartoDB/cartodb,CartoDB/cartodb,codeandtheory/cartodb,raquel-ucl/cartodb,thorncp/cartodb,nyimbi/cartodb,bloomberg/cartodb,CartoDB/cartodb,nuxcode/cartodb,splashblot/dronedb,future-analytics/cartodb,bloomberg/cartodb,future-analytics/cartodb,dbirchak/cartodb,nuxcode/cartodb,dbirchak/cartodb,raquel-ucl/cartodb,raquel-ucl/cartodb,codeandtheory/cartodb,DigitalCoder/cartodb,codeandtheory/cartodb,raquel-ucl/cartodb,splashblot/dronedb,dbirchak/cartodb,CartoDB/cartodb,dbirchak/cartodb,UCL-ShippingGroup/cartodb-1,bloomberg/cartodb,nuxcode/cartodb