Fix network mode for lxc 1.0

Fixes #5692

This change requires lxc 1.0+ to work and breaks lxc versions less than
1.0 for host networking.  We think that this is a find tradeoff by
bumping docker to only support lxc 1.0
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Merge pull request #5946 from crosbymichael/lxc-host-net

Fix network mode for lxc 1.0