Temporarily disabled KillTaskBetweenRunTaskPart test due to MESOS-1945.
Fixed ZooKeeper 3.4.5 OSX Yosemite build.

Fixes build issue caused by htonll introduced by OSX 10.10 (Yosemite).

This poses as a hotfix to prevent us from having to upgrade the bundled
ZooKeeper altogether to prevent longer regression testing. Once
ZooKeeper does get updated into a recent version (3.4.x >= 3.4.7,
3.5.x >= 3.5.1 or >= 3.6.0), this patch should get removed.

Review: https://reviews.apache.org/r/26571
Consolidated "launch" code paths in Docker containerizer.

Review: https://reviews.apache.org/r/26610
Allow docker containers to be scheduled for removal
Fix docker flaky tests

Conflicts:
	src/slave/containerizer/docker.cpp
Add priviledged option to docker info
Support lxc configurations in docker containerizer
Add docker hostname option.
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