fyi - i am unable to reproduce this when using subprocess32 instead of subprocess.  https://pypi.python.org/pypi/subprocess32

That is what i recommend _anyone_ using Python 2.x use instead.

Regardless if this was reintroduced in 2.7.5 we need to re-fix it.

i haven't tested 3.2 or 3.3 or default yet (given the backport isn't showing the problem i'm hoping they don't either but they need testing).