lang/python-doc-html: Update to 2.7.10

The FreeBSD Python team welcomes Python 2.7.10 to the Ports tree!

Announcement: https://www.python.org/downloads/release/python-2710/
Changelog: https://hg.python.org/cpython/raw-file/v2.7.10/Misc/NEWS

Important changes for this release:

• Python 2.7.10 is a bug fix release of the Python 2.7.x series.
• Fixes issues with LibreSSL 2.2+

PR: 192511, 201088
Differentialr Revision: D2637
Reviewed by: koobs (mentor), vsevolod (mentor), antoine
Approved by: koobs (mentor)