Try explicitly installing python3.5 and 2.7.
Try explicitly installing python3.5 and 2.7.

For some reason when I asked to install python3-venv python3 didn't
install but in build [#33](https://travis-ci.org/winksaville/baremetal-hi/builds/88131902)
is worked fine.

So in this test, no venv.

winksaville/baremetal-hi,winksaville/baremetal-hi