removed sys.platform check & consolidated the pip invocations
removed sys.platform check & consolidated the pip invocations

The sys.platform check in need_pip_upgrade  was doing effectively the same pip invocation regardless of what
platform we were evaluating to.

Additionally, removed some duplicate definitions of the python variable which was already in scope
higher up in the function.

szeged/servo,emilio/servo,sadmansk/servo,splav/servo,SimonSapin/servo,emilio/servo,larsbergstrom/servo,ConnorGBrewster/servo,KiChjang/servo,KiChjang/servo,DominoTree/servo,sadmansk/servo,larsbergstrom/servo,szeged/servo,splav/servo,KiChjang/servo,jimberlage/servo,KiChjang/servo,cbrewster/servo,splav/servo,szeged/servo,KiChjang/servo,notriddle/servo,szeged/servo,pyfisch/servo,DominoTree/servo,larsbergstrom/servo,DominoTree/servo,jimberlage/servo,sadmansk/servo,saneyuki/servo,szeged/servo,paulrouget/servo,notriddle/servo,SimonSapin/servo,ConnorGBrewster/servo,dati91/servo,larsbergstrom/servo,emilio/servo,pyfisch/servo,pyfisch/servo,peterjoel/servo,dati91/servo,peterjoel/servo,jimberlage/servo,saneyuki/servo,dati91/servo,paulrouget/servo,pyfisch/servo,ConnorGBrewster/servo,KiChjang/servo,ConnorGBrewster/servo,SimonSapin/servo,jimberlage/servo,peterjoel/servo,paulrouget/servo,saneyuki/servo,szeged/servo,larsbergstrom/servo,cbrewster/servo,pyfisch/servo,dati91/servo,dati91/servo,saneyuki/servo,nnethercote/servo,SimonSapin/servo,notriddle/servo,larsbergstrom/servo,nnethercote/servo,saneyuki/servo,DominoTree/servo,DominoTree/servo,saneyuki/servo,jimberlage/servo,cbrewster/servo,dati91/servo,emilio/servo,DominoTree/servo,notriddle/servo,peterjoel/servo,notriddle/servo,peterjoel/servo,pyfisch/servo,KiChjang/servo,nnethercote/servo,cbrewster/servo,splav/servo,notriddle/servo,larsbergstrom/servo,paulrouget/servo,KiChjang/servo,szeged/servo,SimonSapin/servo,larsbergstrom/servo,DominoTree/servo,jimberlage/servo,splav/servo,peterjoel/servo,sadmansk/servo,nnethercote/servo,nnethercote/servo,DominoTree/servo,szeged/servo,szeged/servo,splav/servo,SimonSapin/servo,paulrouget/servo,emilio/servo,sadmansk/servo,nnethercote/servo,KiChjang/servo,emilio/servo,saneyuki/servo,cbrewster/servo,splav/servo,paulrouget/servo,ConnorGBrewster/servo,jimberlage/servo,emilio/servo,notriddle/servo,DominoTree/servo,cbrewster/servo,KiChjang/servo,notriddle/servo,sadmansk/servo,paulrouget/servo,notriddle/servo,saneyuki/servo,splav/servo,nnethercote/servo,paulrouget/servo,paulrouget/servo,ConnorGBrewster/servo,nnethercote/servo,larsbergstrom/servo,emilio/servo,jimberlage/servo,cbrewster/servo,peterjoel/servo,sadmansk/servo,saneyuki/servo,jimberlage/servo,sadmansk/servo,larsbergstrom/servo,emilio/servo,SimonSapin/servo,pyfisch/servo,ConnorGBrewster/servo,peterjoel/servo,pyfisch/servo,dati91/servo,SimonSapin/servo,saneyuki/servo,pyfisch/servo,peterjoel/servo,cbrewster/servo,pyfisch/servo,emilio/servo,nnethercote/servo,splav/servo,splav/servo,szeged/servo,peterjoel/servo,ConnorGBrewster/servo,notriddle/servo,dati91/servo,nnethercote/servo,paulrouget/servo,DominoTree/servo