os-net-config failing in master ovb jobs

[wes hayutin]

https://logs.rdoproject.org/openstack-periodic/git.openstack.org/openstack-infra/tripleo-ci/master/periodic-tripleo-ci-centos-7-ovb-3ctlr_1comp-featureset001-master/988bda1/logs/undercloud/home/zuul/overcloud_deploy.log.txt.gz#_2019-01-10_01_57_54

 Error in 'ip route add 0.0.0.0/0 via 10.0.0.1 dev br-ex', restarting br-ex:\nUnexpected error while running command.\nCommand: /sbin/ip route add 0.0.0.0/0 via 10.0.0.1 dev br-ex\nExit code: 1\nStdout: u''\nStderr: u'Object \"route add 0.0.0.0/0 via 10.0.0.1 dev br-ex\" is unknown,

This may be a rdo-cloud issue, this needs further investigation.

Stable branches appear to be working recently, only stein/master is failing through out Jan 09, 2019. However the latest stable branch builds in Jan 10 also are failing now.