Dont spawn vlan-tagged ifaces on slave nodes with net check

To generate tagged traffic between fuel slave nodes
we dont need to create tagged interfaces.
Insteed we just can add 8021q tag with specified vlan.

In such case we can run net_check with 3000 vlans in 2 mins.
Tested on 2 nodes setup.

Also it makes possible to run net_check for neutron
with vlan type segmentation.

Change-Id: I638845a21067db954c4876aef19034b2317676ff
Merge "Dont spawn vlan-tagged ifaces on slave nodes with net check"