container/lxc: Fixes showing host_name of veth pair in lxc info
container/lxc: Fixes showing host_name of veth pair in lxc info

This now reads from volatile data if not available from kernel.

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

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