Tom Tromey was ok with the change, but suggested to add a test as well.
Then I forgot about this patch until today. So here it is again, with the
corresponding test.
The problem is that the =thread-exited event does not appear when detaching
from a local process. It does appear with remote though. It's not a really
big deal, but I'd like it to be consistent.
Tested with local and remote Linux on my Ubuntu 14.04.