Add a sleep between HipChat summary and body requests

Test Plan: I tried to run this code locally, but for some reason my edits were not recognized. Is there something special you have to do for local GAE to re-read the third_party libraries? I suppose I could have restarted my server, but I figured this was a simple enough change that I gave up.

Reviewers: csilvers, chris

Subscribers: jace

Differential Revision: http://phabricator.khanacademy.org/D11706
Move sleep into the summary branch