lxd/network/network/utils: Updates GetLeaseAddresses to return only net.IP list
lxd/network/network/utils: Updates GetLeaseAddresses to return only net.IP list

 - Removes IPv6 neighbour look as was out of scope for this function's name.
 - Returns []net.IP rather than []api.InstanceStateNetworkAddress.

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

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