[jump] Enable jumbo frames for vnet devices

[jump] Enable jumbo frames for vnet devices

By default, vnet devices have a MTU of 1500 on the host side, causing
issue with larger packets traversing the bridges between guest VMs
when guest VMs have jumbo frames enabled.

JIRA: FUEL-336
JIRA: FUEL-367
JIRA: FUEL-382

[1] http://linuxaleph.blogspot.com/2013/01/
    how-to-network-jumbo-frames-to-kvm-guest.html
[2] https://packetpushers.net/udev/

Change-Id: I941ac9cf764e3b3fa2d6463be5363b5459775f29
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>