Factor out common part of Servo_ParseProperty() and set_property().
Factor out common part of Servo_ParseProperty() and set_property().

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