[Piglit] ctrl-c to stop piglit run

[Tapani Pälli]

Hello;

I would like Piglit run to stop when hitting ctrl-c, this is because of 
sometimes launching it with wrong parameters, I'm lazy and don't like to 
use kill (like with yum and some others) when I want it to stop.

I tried to implement this via setting signal handler to catch it but 
this does not seem to work. I've tried this in run.py (in run) as well 
as profile.py (in TestProfile class) and I'm getting a feeling that this 
approach does not work because of using a thread pool (multiprocessing). 
What would be the correct way to implement this?

// Tapani