qemu|qtest: Avoid dangerous arguments
The list object is mutable in python and potentially might modify other
object's arguments when used as default argument. Reproducer:
>>> vm1 = QEMUMachine("qemu")
>>> vm2 = QEMUMachine("qemu")
>>> vm1._wrapper.append("foo")
>>> print vm2._wrapper
['foo']
In this case the `args` is actually copied so it would be safe to keep
it, but it's not a good practice to keep it. The same issue applies in
inherited qtest module.
Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-Id: <
20170818142613.32394-3-ldoktor@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>