Remove several non-updated blogs from Planet WebKit

Remove several non-updated blogs from Planet WebKit
https://bugs.webkit.org/show_bug.cgi?id=92973

Reviewed by Eric Seidel.

Adam Treat's blog was last updated in 2009.
Justin Haygood's blog was last updated in 2008.
Mike Smith seems to have moved to Google+ entirely.
Pierre-Luc Beaudoin's blog is unavailable, cached copy says the last (non-WebKit specific update) was in 2010.
Cameron Zwarich' summer of JSC no longer exists.
Anthony Ricaud's blog was last updated in 2009.

* config.ini:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@125075 268f45cc-cd09-0410-ab3c-d52691b4dbfc