branch fix-letsencrypt created (now a252238)

[Leo Famulari]

lfam pushed a change to branch fix-letsencrypt
in repository guix.

        at  a252238   gnu: python-pyopenssl: Update to 16.0.0.

This branch includes the following new commits:

       new  e7a036b   gnu: python-pytest: Update to 2.7.3.
       new  c47fd11   gnu: python-cryptography, python-cryptography-vectors: 
Update to 1.3.1.
       new  a252238   gnu: python-pyopenssl: Update to 16.0.0.

The 3 revisions listed above as "new" are entirely new to this
repository and will be described in separate emails.  The revisions
listed as "adds" were already present in the repository and have only
been added to this reference.