ip_lib netns.execute should work with or without namespace

[Carl Baldwin]

There are a number of places in the neutron code that run an ip command like this:

        if self.network.namespace:
            ip_wrapper = ip_lib.IPWrapper(self.root_helper,
                                          self.network.namespace)
            ip_wrapper.netns.execute(cmd)
        else:
            utils.execute(cmd, self.root_helper)

This code could be simplified if netns.execute simply checked if there was a namespace defined or not.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/77788

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/77788
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=40390598c5a440d1bbfa4f229130eeedf5cd4dba
Submitter: Jenkins
Branch: master

commit 40390598c5a440d1bbfa4f229130eeedf5cd4dba
Author: Carl Baldwin <email address hidden>
Date: Tue Mar 4 04:24:55 2014 +0000

    Refactor netns.execute so that it is not necessary to check namespace

    I saw some code in a couple of reviews today that check whether a
    namespace is set and run it under "ip netns exec ..." if it is.
    Otherwise, it runs the command without it in the default namespace.

    Change-Id: I55e8f4f3523ec7a7c5a6f082addf918952a05741
    Closes-Bug: #1287524