Also make the build go into the tools/devops directory, which will run
shellcheck on the bash files. This also required fixing a couple of issues in
one of the bash scripts.
We currently don't use yamllint, but that's coming very soon.
This change perse does not do other thing than removing the use of
virtuanenv and remove the installation of python-magic.
We have taken this approach because the images that will be used to provision the CI
bots will have python-magic installed by default. We want to do this
because:
1. CI should not be modifying the machine, we do not install any pkg.
2. python-magic should be present, if not, we will get an import error
and we will know how to fix it (re-image).