Update MASTER_SITE_CHEESESHOP

Move files.pythonhosted.org mirror to the top

The mirror pypi.python.org soon will be replaced with the
new Warehouse [1][2], now it's only serving the old files
and its returning 404 - Not Found to the new files hosted

[1] https://pypi.org
[2] https://github.com/pypa/warehouse

Approved by: garga (mentor), python (sunpoet)
Differential Revision: https://reviews.freebsd.org/D11420