Update mod_wsgi.rb

Added --disable-framework flag to configure to get this to work on Mountain Lion.
Just creating the symlink between XcodeDefault.xctoolchain and OSX10.8.xctoolchain (the popular solution) did not work on my Mountain Lion install. I was trying to do everything in Homebrew, but mod_wsgi always failed. What I did is described here https://gist.github.com/talonsensei/6284446 

Propose to add this flag to the formula.

Thanks!

Mark