Fixed containerizer not receiving calls when launching.

Review: https://reviews.apache.org/r/26486
Reverted accidental change to apply-review.sh
Schedule docker containers for removal.

Instead of removing docker containers right after reap, schedule it to
be removed later.

Review: https://reviews.apache.org/r/26861
Fixed docker flaky tests.

Docker tests are flaky, mostly around getting expected output from the
docker container forwarded to stdout/stderr.

This is due to Docker not always have the stdout/stderr output
available for docker logs if kill/rm is called.

Review: https://reviews.apache.org/r/26862
Add priviledged option to docker info
Support arbitrary parameters in docker containerizer
Add docker hostname option.

Conflicts:
	src/docker/docker.cpp
Symlink sandbox directories in docker containerizer

Review: https://reviews.apache.org/r/26517
Avoid docker inspect on each usage call

Review: https://reviews.apache.org/r/26436
Fix typo in DockerInfo protobuf comment
Fixed Command Executor when shell is false.

Review: https://reviews.apache.org/r/26622
Stop instead of kill docker containers on destroy.

Review: https://reviews.apache.org/r/26736