[Devstack] Increase default NIC numbers for VMs to 2
[Devstack] Increase default NIC numbers for VMs to 2

In real world hardware node will have more than 1 NIC, this patch
increase default NIC count to 2 which will allow to test more
realistic scenarios.

Change-Id: I01a45127643e415382ff0897c6b2fb363c7a96fd

openstack/ironic,SauloAislan/ironic,SauloAislan/ironic,pshchelo/ironic,openstack/ironic,pshchelo/ironic