Windows, CI: print the version of BOOTSTRAP_BAZEL
Windows, CI: print the version of BOOTSTRAP_BAZEL

This will help diagnose
https://github.com/bazelbuild/bazel/issues/2977,
which I believed to have been fixed by the release
of 0.5.0, however it seems to have failed once
more with 0.5.0, alas without knowing the actual
bootstrap bazel's version I cannot be sure.

Change-Id: I71e100c549b4ef30699efe6363b72eb792ad1c23
PiperOrigin-RevId: 158243584

aehlig/bazel,werkt/bazel,twitter-forks/bazel,safarmer/bazel,aehlig/bazel,davidzchen/bazel,meteorcloudy/bazel,bazelbuild/bazel,aehlig/bazel,perezd/bazel,cushon/bazel,ButterflyNetwork/bazel,damienmg/bazel,safarmer/bazel,aehlig/bazel,damienmg/bazel,safarmer/bazel,dropbox/bazel,spxtr/bazel,ButterflyNetwork/bazel,variac/bazel,safarmer/bazel,dslomov/bazel-windows,bazelbuild/bazel,katre/bazel,dslomov/bazel-windows,meteorcloudy/bazel,aehlig/bazel,snnn/bazel,werkt/bazel,ulfjack/bazel,dropbox/bazel,ButterflyNetwork/bazel,werkt/bazel,variac/bazel,twitter-forks/bazel,werkt/bazel,dslomov/bazel,cushon/bazel,dslomov/bazel-windows,aehlig/bazel,dropbox/bazel,perezd/bazel,bazelbuild/bazel,twitter-forks/bazel,spxtr/bazel,spxtr/bazel,spxtr/bazel,davidzchen/bazel,katre/bazel,damienmg/bazel,variac/bazel,dslomov/bazel,dropbox/bazel,katre/bazel,werkt/bazel,twitter-forks/bazel,akira-baruah/bazel,davidzchen/bazel,dslomov/bazel-windows,damienmg/bazel,perezd/bazel,ulfjack/bazel,aehlig/bazel,spxtr/bazel,dslomov/bazel,meteorcloudy/bazel,dslomov/bazel-windows,katre/bazel,dslomov/bazel,ulfjack/bazel,snnn/bazel,meteorcloudy/bazel,akira-baruah/bazel,akira-baruah/bazel,snnn/bazel,davidzchen/bazel,damienmg/bazel,perezd/bazel,akira-baruah/bazel,perezd/bazel,cushon/bazel,ButterflyNetwork/bazel,ulfjack/bazel,spxtr/bazel,ButterflyNetwork/bazel,meteorcloudy/bazel,meteorcloudy/bazel,dslomov/bazel,ulfjack/bazel,ulfjack/bazel,bazelbuild/bazel,damienmg/bazel,variac/bazel,akira-baruah/bazel,dslomov/bazel-windows,werkt/bazel,snnn/bazel,variac/bazel,cushon/bazel,ButterflyNetwork/bazel,damienmg/bazel,twitter-forks/bazel,safarmer/bazel,davidzchen/bazel,twitter-forks/bazel,bazelbuild/bazel,cushon/bazel,variac/bazel,perezd/bazel,safarmer/bazel,variac/bazel,snnn/bazel,katre/bazel,dropbox/bazel,davidzchen/bazel,cushon/bazel,dslomov/bazel,meteorcloudy/bazel,akira-baruah/bazel,snnn/bazel,katre/bazel,bazelbuild/bazel,davidzchen/bazel,dropbox/bazel,snnn/bazel,ulfjack/bazel,spxtr/bazel,perezd/bazel,twitter-forks/bazel,dslomov/bazel