Updated libcontainer subpackage dependencies. Most subpackages now do not depend on their parent ('libcontainer') package. 'namespaces' and 'nsinit' still do.
'namespaces' need to refactored a bit more to move the API part of it to 'libcontainer' package and keep the namespace specific code inside that package.
This change is not expected to break docker.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)