Typo around calling :wake_up_timeout?

In lib/thread/pool.rb +53 the method 'wake_up_timeout' was called as a method on whatever __send__ is supposed to return. This doesn't work in JRuby, nor am I sure if this works anywhere else. Could this be a simple typo?

Sorry for not putting this into a separate branch. Still not fully up on the git etiquette :)