Fix issue on kill, process have to consume child output stream or have t...

Fix issue on kill, process have to consume child output stream or have to waitpid.

If we don't waitpid spawning a new tty session and then kill it will create a bash zombie process.

```
root 1795 0.2 9.6 104212 48500 ? Sl 01:00 1:39 node /opt/controller-app/lib/index.js
root 2914 0.1 0.0 0 0 ? Zs 13:22 0:00 _ [bash] <defunct>
root 3137 0.2 0.0 0 0 ? Zs 13:24 0:00 _ [bash] <defunct> 
```