Make url metadata parsing compatible with new PyPI URLs

[mythmon]

PyPI has added a new kind of URL, using the hash of the file as the directory path instead of a path based on the Python version and the package name. Luckily, we weren't using that information. I changed the URL analyzers to ignore the path in the URL, and only look at the filename. This should be more robust in the future: The filenames are standardized, the path is not.

@peterbe r?

[peterbe]

I trust your code change but I think I ought to try it manually. How can I attempt to do it so it doesn't work using a local virtualenv and then verify that using your patch, instead, it fixes the problem?

[mythmon]

For me, any use of hashin tickles this bug. In particular, I tried running hashin django==1.8.12 -p 3.5 and got a traceback before this patch.

Edit: any use of hashin with the -p flag.

[peterbe]

BUt it has to be with -p ... right? Because I managed to use hashin this morning for a couple of things.

[mythmon]

Er, right. I was using the older version of hashin that parses urls even if you don't filter by Python version.

[peterbe]

I was able to reproduce the error, used your branch and then it worked.

[peterbe]

Version 0.4.2 on its way to PyPI.