This works mostly by refactoring our "main" package to be careful about what it imports based on the daemon build tag. :)
Also, I've updated Travis to test "client-only" compilation after it tests the daemon version.
Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Upstream-commit: 1b95590d06b20b79041f6d23b9bc35612b82cb51
Component: engine