Pingall should be interruptible

[lantz]

Currently mininet shuts down if you interrupt pingall. Instead it should just stop the overall pingall operation and recover.

[bocon13]

This is not an issue if pingall is initiated from the CLI. Is this bug for the pingall test?

[lantz]

Hmm, not sure why I ran into this problem, since I can't reproduce it in the 2.0.0 VM or in master, so I think it's good. net.pingall() should be interrupted if it's running in a script (you can catch exceptions if you like of course.)

I'm closing this out since it does not seem to be an issue at this moment with the master branch. [It's possible it was a bug in another branch - I'll reopen it if necessary in the future.]