Only do complete propfind on 412
Only do complete propfind on 412 or old data, not errors
Only do complete propfind on 412 or old data, not errors
Only do complete propfind on 412 or old data, not errors
Only do complete propfind on 412 or old data, not errors
Merge pull request #55 from pantheon-systems/20130418-nofullpropfind

Only do complete propfind on 412 and out of date. Do not do on 404, 500, and other error conditions