shared/instance: Renames volatile.last_state.vsock_id to volatile.vsock_id
shared/instance: Renames volatile.last_state.vsock_id to volatile.vsock_id

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

stgraber/lxd,stgraber/lxd,hallyn/lxd,hallyn/lxd,stgraber/lxd,stgraber/lxd,lxc/lxd,lxc/lxd,lxc/lxd,stgraber/lxd,stgraber/lxd,stgraber/lxd,lxc/lxd,hallyn/lxd,atxwebs/lxd,atxwebs/lxd,atxwebs/lxd,hallyn/lxd,hallyn/lxd,lxc/lxd,hallyn/lxd,lxc/lxd,lxc/lxd,atxwebs/lxd