Exclude all pages that have been deprecated or had their name changed

[mchristofides]

Several specific pages already accounted for (so that they don't redirect):

• recovery-config
• app-createlang
• app-droplang
• indexcost
• inherit
• manage
• failure
• failure-disk-failed
• programmer-client
• developer

We could find them all, but it looks like a lot of work for possibly not much gain.

Update: The failure case is now much nicer, since adding a notice with a link to the page redirected from (#3).