Starting from version 1.3.5, Libvirt allows to set a vlan tag for macvtap
passthrough mode on SR-IOV VFs. Libvirt also removes any vlan tags that
has been set externally, by the ip link command.
In order to support the older libvirt versions, this code will make
the behaviour backward compatible by checking the libvirt version.
This can be completely removed once the minimum libvirt version will increase.
Change-Id: Ia14e78e0eda81b8d29d5aa6e07e68777665d0710
Closes-Bug: #1657035