Add new interfaces for label/selinux

We need the ability when using --ipc container:ID to match the SELinux label of the
container that the new container is sharing a label with.

Also add the ability to get the option to disable SELinux labeling for a container.

Docker-DCO-1.1-Signed-off-by: Dan Walsh <dwalsh@redhat.com> (github: rhatdan)
Yes we changed the interface yesterday to set all fields. But I don't think we should be checking directly.  We should walk the list looking for lable:type.