devstack 'cleanup-node' script should delete OVS bridges
devstack 'cleanup-node' script should delete OVS bridges

When unstack'ing, cleanup-node.sh needs to also remove the ovs bridges
which were added when creating the node.

Failing to do this will cause subsequent runs of stack.sh to fail
because the bridge can't be re-created.

Change-Id: I5cc36e675d272f6dee3bc667133d1e7e082b0a55
Partial-bug: #1526403

openstack/ironic,ionutbalutoiu/ironic,SauloAislan/ironic,pshchelo/ironic,bacaldwell/ironic,dims/ironic,ionutbalutoiu/ironic,SauloAislan/ironic,NaohiroTamura/ironic,dims/ironic,NaohiroTamura/ironic,devananda/ironic,openstack/ironic,bacaldwell/ironic,pshchelo/ironic