'./mach rustup': Use alternate S3 URL that doesn’t require SNI
'./mach rustup': Use alternate S3 URL that doesn’t require SNI

… to hopefully fix https://travis-ci.org/servo/servo-with-rust-nightly/ builds.

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