Change the hipchat message that goes to 1s and 0s to be short.

Summary:
This is by request -- the deploy message in 1s and 0s just needs to be
a 'this happened' kind of thing, and doesn't need all the details; you
can get those in '1s/0s: deploy' if need be.

Test Plan:
Manually ran
   env PYTHONPATH=$HOME/khan/webapp/third_party:$HOME/khan/webapp python notify.py
and saw it say:

   App Engine default version just changed: None → 0730-1146-bb604a073a1e

in '1s and 0s', while in '1s/0s: deploys' it still says:

   App Engine default version just changed: khanacademy.org, appspot dashboard, app versions
   • old: None (error logs, instances)
   • new: 0730-1146-bb604a073a1e (error logs, instances)

Reviewers: alpert

Reviewed By: alpert

Differential Revision: http://phabricator.khanacademy.org/D11771