`systemctl stop traffic_ops` does not kill all processes

not sure why it gets in this state, but traffic_ops processes sometimes get in a state where the parent process is the root (1) for many of the script/cdn workers. The init.d script doesn't stop them because they don't match the pid in `/var/run/traffic_ops.pid`.

This needs to be more robust.

Example: on my test VM, if I run this, I see multiple parent processes:

ps -ef | grep script/cdn|grep -v root | awk '{print $3}' | sort -u
1
22713
29306