Remove unused metric_key method
Remove unused metric_key method

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