Remove 2 links redirecting to pages that don't contain free books (#3131)

* Removed non-working book link

The link gets redirected to www.oreilly.com. The 1st chapter is still available to read online at https://www.oreilly.com/library/view/python-cookbook-3rd/9781449357337/ch01.html

* Removed another redirected book

The URL is redirected to http://jasonrbriggs.com/python-for-kids/ which is not available for free.

free-programming-books.md

@@ -2137,7 +2137,6 @@ Kerridge (PDF) (email address *requested*, not required)
 * [Python 2.7 quick reference](http://infohost.nmt.edu/tcc/help/pubs/python/web/) - New Mexico Tech (2.7)
 * [Python 3 Official Documentation](https://docs.python.org/3/download.html) (PDF, EPUB, HTML, TEXT) (3.x)
 * [Python 3 Tutorial](https://github.com/Akuli/python-tutorial)
-* [Python Cookbook](http://chimera.labs.oreilly.com/books/1230000000393/index.html) - David Beazley
 * [Python Data Science Handbook](https://github.com/jakevdp/PythonDataScienceHandbook) - Jake VanderPlas (HTML, Jupyter Notebooks)
 * [Python for Everybody Exploring Data Using Python 3](http://py4e.com/book.php) - Charles Severance (PDF, EPUB, HTML)
   * [Python for Informatics: Exploring Information](http://www.pythonlearn.com/book.php) (2.7.5)
@@ -2156,7 +2155,6 @@ Kerridge (PDF) (email address *requested*, not required)
 * [Python Programming](https://upload.wikimedia.org/wikipedia/commons/9/91/Python_Programming.pdf) - Wikibooks (PDF) (2.6)
 * [Scipy Lecture Notes](http://scipy-lectures.github.io)
 * [SICP in Python](http://www-inst.eecs.berkeley.edu/~cs61a/sp12/book/) (3.2)
-* [Snake Wrangling For Kids](http://www.briggs.net.nz/snake-wrangling-for-kids.html) (3.x)
 * [Suporting Python 3: An In-Depth Guide](http://python3porting.com) (2.6 - 2.x & 3.1 - 3.x)
 * [Test-Driven Web Development with Python](http://www.obeythetestinggoat.com/pages/book.html) - Harry Percival (3.3 - 3.x)
 * [Text Processing in Python](http://gnosis.cx/TPiP/) - David Mertz (2.3 - 2.x)