CI: Azure Linux pip upgrade via get-pip.py
CI: Azure Linux pip upgrade via get-pip.py

Also be explicit about using --user, instead of relying on the
Ubuntu-modified pip as before.

Also change "python3" to "python3.6" on Azure Linux build.
Somehow "python3" fails unless "python3-pip" is installed.

Finally, install python3-distutils on Azure Linux; apparently
the python3.6 on Ubuntu Bionic does not include distutils (there
must be a packaging bug report about that, didn't look for it though).

ilayn/scipy,jor-/scipy,anntzer/scipy,aeklant/scipy,Eric89GXL/scipy,arokem/scipy,rgommers/scipy,gertingold/scipy,pizzathief/scipy,jor-/scipy,Stefan-Endres/scipy,e-q/scipy,e-q/scipy,vigna/scipy,ilayn/scipy,vigna/scipy,nmayorov/scipy,aarchiba/scipy,anntzer/scipy,pizzathief/scipy,WarrenWeckesser/scipy,matthew-brett/scipy,arokem/scipy,anntzer/scipy,aarchiba/scipy,jamestwebber/scipy,rgommers/scipy,andyfaff/scipy,tylerjereddy/scipy,gertingold/scipy,zerothi/scipy,WarrenWeckesser/scipy,matthew-brett/scipy,andyfaff/scipy,aarchiba/scipy,rgommers/scipy,person142/scipy,arokem/scipy,rgommers/scipy,e-q/scipy,e-q/scipy,zerothi/scipy,vigna/scipy,gertingold/scipy,pizzathief/scipy,person142/scipy,anntzer/scipy,ilayn/scipy,Eric89GXL/scipy,zerothi/scipy,gertingold/scipy,lhilt/scipy,jamestwebber/scipy,anntzer/scipy,grlee77/scipy,ilayn/scipy,scipy/scipy,scipy/scipy,person142/scipy,matthew-brett/scipy,lhilt/scipy,lhilt/scipy,endolith/scipy,andyfaff/scipy,endolith/scipy,matthew-brett/scipy,matthew-brett/scipy,perimosocordiae/scipy,grlee77/scipy,aeklant/scipy,Eric89GXL/scipy,jamestwebber/scipy,andyfaff/scipy,jamestwebber/scipy,grlee77/scipy,endolith/scipy,andyfaff/scipy,jor-/scipy,Stefan-Endres/scipy,Eric89GXL/scipy,vigna/scipy,zerothi/scipy,perimosocordiae/scipy,scipy/scipy,aarchiba/scipy,pizzathief/scipy,nmayorov/scipy,WarrenWeckesser/scipy,perimosocordiae/scipy,jor-/scipy,aeklant/scipy,tylerjereddy/scipy,person142/scipy,lhilt/scipy,tylerjereddy/scipy,pizzathief/scipy,zerothi/scipy,vigna/scipy,perimosocordiae/scipy,rgommers/scipy,endolith/scipy,e-q/scipy,nmayorov/scipy,mdhaber/scipy,andyfaff/scipy,ilayn/scipy,WarrenWeckesser/scipy,Eric89GXL/scipy,jamestwebber/scipy,zerothi/scipy,perimosocordiae/scipy,scipy/scipy,tylerjereddy/scipy,aarchiba/scipy,person142/scipy,Stefan-Endres/scipy,scipy/scipy,grlee77/scipy,endolith/scipy,Stefan-Endres/scipy,Stefan-Endres/scipy,aeklant/scipy,arokem/scipy,arokem/scipy,WarrenWeckesser/scipy,aeklant/scipy,jor-/scipy,anntzer/scipy,tylerjereddy/scipy,nmayorov/scipy,mdhaber/scipy,lhilt/scipy,Eric89GXL/scipy,grlee77/scipy,gertingold/scipy,scipy/scipy,perimosocordiae/scipy,mdhaber/scipy,nmayorov/scipy,WarrenWeckesser/scipy,endolith/scipy,mdhaber/scipy,mdhaber/scipy,mdhaber/scipy,Stefan-Endres/scipy,ilayn/scipy