Review/Rework _ProactorWritePipeTransport._pipe_closed()?

[GoogleCodeExporter]

Hi,

I just fixed an obvious bug in _pipe_closed():
http://hg.python.org/cpython/rev/c412243b9d61

I don't understand why it was not noticed by the test suite. Maybe we need more 
tests? Or maybe the method became useless? I don't remember in which case 
_pipe_closed() is called while an overlapped write is pending.

Original issue reported on code.google.com by [email protected] on 20 Feb 2014 at 3:59