Comment 3 for bug 1298698

The current version of the patch looks good.

You don't need the map in this line:
        cmd.extend(map(str, params))
It can just be like this:
        cmd.extend(params)

Since the helper function already does that here:
https://github.com/openstack/glance/blob/master/glance/openstack/common/processutils.py#L137

Otherwise, this looks like a very good solution to the problem.