lxd/device/device/utils/network: Allow VLAN ID 0 in networkValidVLAN
lxd/device/device/utils/network: Allow VLAN ID 0 in networkValidVLAN

Openvswitch allows VLAN 0 for untagged frames.

Signed-off-by: Thomas Parrott <6b778ce645fb0e3dde76d79eccad490955b1ae74@canonical.com>

atxwebs/lxd,lxc/lxd,Skarlso/lxd,stgraber/lxd,lxc/lxd,hallyn/lxd,Skarlso/lxd,hallyn/lxd,lxc/lxd,Skarlso/lxd,stgraber/lxd,lxc/lxd,atxwebs/lxd,mjeanson/lxd,hallyn/lxd,atxwebs/lxd,atxwebs/lxd,stgraber/lxd,Skarlso/lxd,hallyn/lxd,mjeanson/lxd,lxc/lxd,stgraber/lxd,lxc/lxd,stgraber/lxd,hallyn/lxd,mjeanson/lxd,stgraber/lxd,lxc/lxd,stgraber/lxd,hallyn/lxd