Fix Python 2.6 builds

The SSL patch file was recently renamed[1], and then fixed to apply
against 2.6.9rc1[2].

[1] https://github.com/collective/buildout.python/commit/ad45adb78bfa37542d62a394392d5146fce5af34
[2] https://github.com/collective/buildout.python/commit/8d58e4b2bc67ef67d97013a66e8aa4669b3a37a1

Since buildout is still building Python 2.6.8 we should use a URL to a
version of the patch that applies to 2.6.8.

I noticed this problem while idly browsing Travis CI:
https://travis-ci.org/buildout/buildout/jobs/12570074