Fix incorrect link to discuss e-mail list

Fix an incorrect link to openvswitch discuss e-mail list on the
Configuration Cookbook index page.
ovscon2014: Complete our collection of slides.

From Justin (thanks!).
ovscon2014: Add note about videos.  Remove mention of robots.
Merge pull request #11 from lowescott/fix-cookbook-discuss-link

Fix incorrect link to discuss e-mail list