Use correct dialect for escaping functions. (#2593)
Use correct dialect for escaping functions. (#2593)

Column functions are currently escaped with the
same dialect that is being used by Superset for its
metadata storage.  Instead the dialect of the target
table should be used when escaping column names.
mistercrunch/panoramix,BRD-CD/superset,asdf2014/superset,timifasubaa/incubator-superset,nekia/incubator-superset-dev,nekia/incubator-superset-dev,timifasubaa/incubator-superset,apache/incubator-superset,zhouyao1994/incubator-superset,BRD-CD/superset,alanmcruickshank/superset-dev,nekia/incubator-superset-dev,zhouyao1994/incubator-superset,zhouyao1994/incubator-superset,alanmcruickshank/superset-dev,FrederichCheng/incubator-superset,nekia/incubator-superset-dev,SingTel-DataCo/incubator-superset,airbnb/superset,dmigo/incubator-superset,airbnb/caravel,zhouyao1994/incubator-superset,SingTel-DataCo/incubator-superset,asdf2014/superset,massgov/incubator-superset,dmigo/incubator-superset,dmigo/incubator-superset,robert-digit/superset,mistercrunch/panoramix,massgov/incubator-superset,alanmcruickshank/superset-dev,mistercrunch/panoramix,robert-digit/superset,airbnb/caravel,apache/incubator-superset,zhouyao1994/incubator-superset,massgov/incubator-superset,asdf2014/superset,alanmcruickshank/superset-dev,massgov/incubator-superset,timifasubaa/incubator-superset,apache/incubator-superset,ArijanaBrlek/superset,SingTel-DataCo/incubator-superset,ArijanaBrlek/superset,airbnb/superset,dmigo/incubator-superset,robert-digit/superset,robert-digit/superset,BRD-CD/superset,airbnb/caravel,asdf2014/superset,SingTel-DataCo/incubator-superset,airbnb/caravel,airbnb/superset,airbnb/superset,BRD-CD/superset,FrederichCheng/incubator-superset,ArijanaBrlek/superset,apache/incubator-superset,mistercrunch/panoramix,FrederichCheng/incubator-superset,timifasubaa/incubator-superset,apache/incubator-superset,FrederichCheng/incubator-superset,ArijanaBrlek/superset