remove setupDev from libcontainer

Docker-DCO-1.1-Signed-off-by: Victor Vieux <victor.vieux@docker.com> (github: vieux)
Update test to reallocate port
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
add test

Docker-DCO-1.1-Signed-off-by: Victor Vieux <victor.vieux@docker.com> (github: vieux)
Merge pull request #4958 from crosbymichael/update-port-tests

Update test to reallocate port
Merge pull request #4942 from vieux/cleanup_dev_libcontainer

remove setupDev from libcontainer