solve caching problem+discussion

This is still a significant problem for people installing wagn.

Hard to test, as it was flaky, but i haven't seen this recently. Have any of you?

  --John Abbe.....Wed May 20 21:03:47 -0700 2009

this is clearly fixed on our servers, but people installing wagn are clearly still encountering issues.

  --Ethan McCutchen.....Thu May 21 08:46:35 -0700 2009

remaining task: fix rake:cache_clear on clusters

  --Ethan McCutchen.....Tue Jun 02 09:25:21 -0700 2009

also, investigate icah weirdness

  --Lewis Hoffman.....Tue Jun 02 09:27:05 -0700 2009

rake cache:clear is fixed for cluster. also sandbox reset includes cache clear. Ethan discovered wierdness in icah data, still not sure how it got there, but problem is handled for now.

  --Lewis Hoffman.....Fri Jun 05 09:38:16 -0700 2009

icah weirdness was a trash (not cache) problem.

  --Ethan McCutchen.....Fri Jun 05 10:08:44 -0700 2009