subprocess_exec/shell: raise errors on invalid arguments; force bufsize to 0

[GoogleCodeExporter]

subprocess_exec/shell should always raise errors on invalid arguments, even if 
"python -O" is used (when assertions are disabled).

And asyncio doesn't use buffered file objects for pipes, so the buffer size can 
be fixed to 0. No need to pass bufsize to each function.

See attached patch.

Original issue reported on code.google.com by victor.s...@gmail.com on 29 Jan 2014 at 12:17

Attachments:

• bufsize.patch