Add proper support for the new media/ext directory on installation.
Review Request #2606 — Created Sept. 22, 2011 and submitted
Add proper support for the new media/ext directory on installation. RB 1.7's extension support requires a writable media/ext directory. rb-site and prepare-dev now create it, and the manual updates checks make sure we can write it.
Performed a new installation and upgraded an existing one. In each case, the directory was created and I was told I needed to set permissions. When I ignored that advice, I saw a manual updates page forcing me to update them.