[Buildroot] [git commit] support/testing: drop explicit docker kernel options from docker test

[Peter Korsgaard]

commit: https://git.buildroot.net/buildroot/commit/?id=436daadc42f4b92c2103b273df86bd2c7161e644
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/master

Since commit 0390777bfaff6c6 (package/docker-engine: needs some kernel
options), docker-engine now automatically ensures the needed kernel options
are enabled, so drop the explicit options from the kernel config.

23:19:27 TestDockerCompose                        Starting
23:19:28 TestDockerCompose                        Building
00:14:41 TestDockerCompose                        Building done
00:15:30 TestDockerCompose                        Cleaning up