Fix incorrect flag syntax in regen.py.
Fix incorrect flag syntax in regen.py.

This is a regression from #13079.

jimberlage/servo,dati91/servo,anthgur/servo,jimberlage/servo,peterjoel/servo,peterjoel/servo,mbrubeck/servo,jimberlage/servo,fiji-flo/servo,peterjoel/servo,fiji-flo/servo,notriddle/servo,upsuper/servo,nnethercote/servo,nnethercote/servo,splav/servo,KiChjang/servo,KiChjang/servo,nnethercote/servo,larsbergstrom/servo,mbrubeck/servo,notriddle/servo,szeged/servo,mattnenterprise/servo,KiChjang/servo,larsbergstrom/servo,szeged/servo,szeged/servo,pyfisch/servo,anthgur/servo,canaltinova/servo,CJ8664/servo,pyfisch/servo,SimonSapin/servo,splav/servo,anthgur/servo,DominoTree/servo,emilio/servo,peterjoel/servo,emilio/servo,DominoTree/servo,SimonSapin/servo,dsandeephegde/servo,ConnorGBrewster/servo,sadmansk/servo,jimberlage/servo,DominoTree/servo,DominoTree/servo,dati91/servo,avadacatavra/servo,rnestler/servo,nnethercote/servo,paulrouget/servo,emilio/servo,nnethercote/servo,DominoTree/servo,notriddle/servo,pyfisch/servo,CJ8664/servo,KiChjang/servo,mattnenterprise/servo,sadmansk/servo,sadmansk/servo,mattnenterprise/servo,sadmansk/servo,ConnorGBrewster/servo,SimonSapin/servo,canaltinova/servo,mattnenterprise/servo,notriddle/servo,peterjoel/servo,jimberlage/servo,mattnenterprise/servo,pyfisch/servo,szeged/servo,SimonSapin/servo,emilio/servo,upsuper/servo,splav/servo,splav/servo,splav/servo,thiagopnts/servo,notriddle/servo,saneyuki/servo,saneyuki/servo,thiagopnts/servo,splav/servo,jimberlage/servo,szeged/servo,dati91/servo,eddyb/servo,SimonSapin/servo,upsuper/servo,canaltinova/servo,thiagopnts/servo,rnestler/servo,rnestler/servo,cbrewster/servo,cbrewster/servo,emilio/servo,nnethercote/servo,emilio/servo,eddyb/servo,eddyb/servo,dsandeephegde/servo,CJ8664/servo,notriddle/servo,larsbergstrom/servo,szeged/servo,thiagopnts/servo,cbrewster/servo,dsandeephegde/servo,anthgur/servo,upsuper/servo,dati91/servo,splav/servo,sadmansk/servo,saneyuki/servo,DominoTree/servo,fiji-flo/servo,eddyb/servo,canaltinova/servo,ConnorGBrewster/servo,paulrouget/servo,mattnenterprise/servo,peterjoel/servo,paulrouget/servo,cbrewster/servo,ConnorGBrewster/servo,DominoTree/servo,avadacatavra/servo,SimonSapin/servo,saneyuki/servo,rnestler/servo,pyfisch/servo,pyfisch/servo,dati91/servo,cbrewster/servo,DominoTree/servo,fiji-flo/servo,cbrewster/servo,KiChjang/servo,fiji-flo/servo,avadacatavra/servo,pyfisch/servo,fiji-flo/servo,larsbergstrom/servo,splav/servo,ConnorGBrewster/servo,upsuper/servo,anthgur/servo,eddyb/servo,avadacatavra/servo,canaltinova/servo,KiChjang/servo,sadmansk/servo,rnestler/servo,emilio/servo,notriddle/servo,mbrubeck/servo,saneyuki/servo,ConnorGBrewster/servo,jimberlage/servo,saneyuki/servo,rnestler/servo,dsandeephegde/servo,thiagopnts/servo,cbrewster/servo,saneyuki/servo,paulrouget/servo,larsbergstrom/servo,DominoTree/servo,splav/servo,larsbergstrom/servo,mbrubeck/servo,ConnorGBrewster/servo,rnestler/servo,CJ8664/servo,szeged/servo,thiagopnts/servo,ConnorGBrewster/servo,fiji-flo/servo,dati91/servo,notriddle/servo,emilio/servo,avadacatavra/servo,dsandeephegde/servo,CJ8664/servo,mbrubeck/servo,KiChjang/servo,anthgur/servo,cbrewster/servo,KiChjang/servo,dati91/servo,notriddle/servo,paulrouget/servo,anthgur/servo,mbrubeck/servo,canaltinova/servo,eddyb/servo,peterjoel/servo,jimberlage/servo,nnethercote/servo,KiChjang/servo,sadmansk/servo,paulrouget/servo,mattnenterprise/servo,avadacatavra/servo,pyfisch/servo,upsuper/servo,eddyb/servo,paulrouget/servo,CJ8664/servo,larsbergstrom/servo,paulrouget/servo,peterjoel/servo,szeged/servo,thiagopnts/servo,eddyb/servo,DominoTree/servo,CJ8664/servo,rnestler/servo,peterjoel/servo,canaltinova/servo,thiagopnts/servo,larsbergstrom/servo,nnethercote/servo,splav/servo,mattnenterprise/servo,SimonSapin/servo,jimberlage/servo,emilio/servo,saneyuki/servo,avadacatavra/servo,peterjoel/servo,mbrubeck/servo,paulrouget/servo,dsandeephegde/servo,CJ8664/servo,szeged/servo,saneyuki/servo,larsbergstrom/servo,SimonSapin/servo,saneyuki/servo,emilio/servo,larsbergstrom/servo,pyfisch/servo,nnethercote/servo,avadacatavra/servo,upsuper/servo,nnethercote/servo,sadmansk/servo,notriddle/servo,fiji-flo/servo,anthgur/servo,pyfisch/servo,KiChjang/servo,szeged/servo,dsandeephegde/servo,dsandeephegde/servo,upsuper/servo,mbrubeck/servo,canaltinova/servo,paulrouget/servo,dati91/servo