This PR adds a test and fix for the issue described in bpo-34132, a strange regression in netrc parsing that causes recent versions of Python 3 to fail to parse files like this:

# Comment
default login user password pass 

but to succesfully parse files like this:

#Comment
default login user password pass 

This fix is adapted from the Python 2 version, which is able to parse the former file.

https://bugs.python.org/issue34132