Removes unneeded DefinePlugin entries.
Removes unneeded DefinePlugin entries.

oyeanuj/react-universally,igorsvee/react-ssr,diondirza/react-universally,kennethtruong/react-webapp,pebie/react-universally-node-config,deanslamajr/trakta.co,sergiokopplin/react-universally,ueno-llc/starter-kit-universally,ctrlplusb/react-universally,ueno-llc/starter-kit-universally,brettsnaidero/bsd,LorbusChris/react-universally