Updated openstack/openstack
Project: openstack/neutron  1bba7125c4c16556a0b1bed63d22ed406a0d1c3d
null
Remove device_exists in LinuxBridgeManager

LinuxBridgeManager is adding a device_exists method instead of
using the one in ip_lib as the rest of the codebase

Change-Id: Ibeb95be76a1e1b20c69841e708c2a2cbf1cbe05a
Closes-Bug: #1302463