This drops support for migrations from pre-1.10 Docker versions, which
should be done via an external tool or an intermediate upgrade.
Signed-off-by: Justin Cormack <justin.cormack@docker.com>
The LXC driver was deprecated in Docker 1.8.
Following the deprecation rules, we can remove a deprecated feature
after two major releases. LXC won't be supported anymore starting on Docker 1.10.
Signed-off-by: David Calavera <david.calavera@gmail.com>
