Using Vagrant makes reproducing and debugging CI issues easier: after
"vagrant up", a test virtual machine is up and running, and ready to run
"fedora-test-runner.sh". In order to make using this VM even easier, a
helper script, "run-selinux-test.sh" is created inside and instructions
on how to use it are documented at the beginning of Vagrantfile.
Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>