Normally, when you launch a Docker container, the process you're
executing becomes PID 1, giving it the quirks and responsibilities that
come with being the init system for the container.

There are two common issues this presents:

* In most cases, signals won't be handled properly.
* Orphaned zombie processes aren't properly reaped.

the dumb-init acting like a simple init system. It launches a single
process and then proxies all received signals to a session rooted at
that child process.

Closes-Bug: #1614509
Change-Id: I9d3d04648e151ddc7c6732b92ffd3b6c9fe467ec