It should be avoided to import cmd/podman/... packages from outside of
cmd/podman. This can lead in weird hard to debug import paths but also
can have negative consequences when imported in unit tests. In this case
it will set XDG_CONFIG_HOME and thus the machine tests this dir over the
tmp HOME env variable which is set at a later point. This caused machine
files to be leaked into the actual users home dir.
Signed-off-by: Paul Holzinger <pholzing@redhat.com>