Use "ip" commands to replace "ifconfig" commands
Use "ip" commands to replace "ifconfig" commands

It seems the 'ifconfig' does not exist on some CI hosts.
And neutron related commands are also using ip commands.

Change-Id: Id549340b8420423c92ee9443b9fd203aacffa89e
Closes-bug: 1670952

openstack/tacker,stackforge/tacker,openstack/tacker,openstack/tacker,zeinsteinz/tacker,stackforge/tacker,zeinsteinz/tacker