Convert Linux Bridge os-vif driver to use native Python bindings

[Stephen Finucane]

The pyroute2 package provides native Python bindings for netlink and Linux network configuration. We should use this instead of calling binaries provided by the iproute2 project (ip-link et al).

Like bug #1666917, this will improve performance, reduce memory footprint and improve security by reducing use of processutils.

[Stephen Finucane (stephenfinucane)]

Neutron already uses this library [1] so it's likely in g-r.

[1] https://github.com/openstack/neutron/blob/eeeee06b/neutron/privileged/agent/linux/ip_lib.py

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/451433

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/484386

[OpenStack Infra (hudson-openstack)]

Change abandoned by Stephen Finucane (<email address hidden>) on branch: master
Review: https://review.openstack.org/451433
Reason: Rodolfo is doing this now

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/531358

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/484386
Committed: https://git.openstack.org/cgit/openstack/os-vif/commit/?id=dff9093ab682d798e6165840cfae234f2a5372f5
Submitter: Zuul
Branch: master

commit dff9093ab682d798e6165840cfae234f2a5372f5
Author: Rodolfo Alonso Hernandez <email address hidden>
Date: Mon Jul 17 15:27:53 2017 +0100

    Migrate from 'ip' commands to 'pyroute2'

    This patch migrates the use of command line 'ip' commands
    to pyroute2 library. A new class, 'IpCommand', is created
    to wrap the use of the library, implementing the functionalities
    needed in this project.

    The new wrapper class is defined in 'os_vif' and is used in
    'vif_plug_linux_bridge' and 'vif_plug_ovs'.

    This patch also adds functional tests in 'os_vif'. The aim
    of these functional tests is to check 'pyroute2' implementation
    works correctly, by creating, modifying and deleting network
    interfaces. 'ip' commands are used to execute additional actions,
    not relying on the tested library to check its own results.

    Co-Authored-By: Stephen Finucane <email address hidden>

    Closes-Bug: #1677238
    Change-Id: I18f7b3424a6c447ee89df1f0326ece75f2333bf2

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/os-vif 1.8.0 release.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/531358
Committed: https://git.openstack.org/cgit/openstack/os-vif/commit/?id=4e7ce55d102292215b9dae8deeab90efc96735dd
Submitter: Zuul
Branch: master

commit 4e7ce55d102292215b9dae8deeab90efc96735dd
Author: Stephen Finucane <email address hidden>
Date: Fri Jan 5 10:44:16 2018 +0000

    Configure privsep binary

    This is necessary because we're combining virtualenv's and sudo. sudo
    doesn't passthrough environment variables by default, so we must do so
    manually.

    Change-Id: I8ef15edd1b8adae0ddad84f71379356ead5d4fd1
    Related-bug: #1677238