Reaper doesn't like sudo'd processes

[coderanger]

In the case where the process doing shell-out-ing is an unpriv'd user, and the command being run either directly or indirectly ends up with elevated perms, we can end up with a situation where the kill() call in reap_errant_child fails with EPERM.

We should probably just ignore it like we do with ESRCH, maybe with a warning that reaping failed due to process permissions.