mount of /.dockerinit is not needed for native driver, so move it into lxc driver

Docker-DCO-1.1-Signed-off-by: Albert Zhang <zhgwenming@gmail.com> (github: zhgwenming)
since moved the ./dockerinit mount into lxc driver, fix the lxc testcase accordingly

Docker-DCO-1.1-Signed-off-by: Albert Zhang <zhgwenming@gmail.com> (github: zhgwenming)
don't allow links to be used with --net=host

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
Merge pull request #6797 from zhgwenming/master

make /.dockerinit bind mount driver specific
Merge pull request #7066 from unclejack/disallow_links_with_nethost

don't allow links to be used with --net=host
Update libcontainer to be85764f109c3f0f62cd2a5c8be
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Don't create pty slave in the daemon for native driver
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Make tty term exec driver specific

lxc is special in that we cannot create the master outside of the
container without opening the slave because we have nothing to provide to the
cmd.  We have to open both then do the crazy setup on command right now instead of
passing the console path to lxc and telling it to open up that console.  we save a couple of
openfiles in the native driver because we can do this.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Fix cross compile non cgo and linux systems
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)