Update pypi_spec.rb

Change line 68 to designate the correct server.  It appears there may have been a recent change to PYPI system settings. Deploying to the old url will succeed, but the package will never be updated on the main PyPi repo.

More information regarding this problem: https://bitbucket.org/pypa/pypi/issue/123/sdist-upload-returns-success-but-no-new