python/machine: Disable pylint warning for open() in _pre_launch

python/machine: Disable pylint warning for open() in _pre_launch

Shift the open() call later so that the pylint pragma applies *only* to
that one open() call. Add a note that suggests why this is safe: the
resource is unconditionally cleaned up in _post_shutdown().

_post_shutdown is called after failed launches (see launch()), and
unconditionally after every call to shutdown(), and therefore also on
__exit__.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Message-id: 20210527211715.394144-6-jsnow@redhat.com
Message-id: 20210517184808.3562549-6-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>