libcontainer.GetNamespace returns nil on FreeBSD because
libcontainer.namespaceList is empty. In this case, Namespaces#Get should
return nil instead of being panic.
Docker-DCO-1.1-Signed-off-by: Kato Kazuyoshi <kato.kazuyoshi@gmail.com> (github: kzys)
Someone probably got really used to typing er on the end of contain :)
Docker-DCO-1.1-Signed-off-by: Brandon Philips <brandon.philips@coreos.com> (github: philips)