Edward Z. Yang authored Feb 20, 2017 and Edward Z. Yang committed Feb 20, 2017

- Setup the ssh key for cabal-website deploy right before we use
  it, so it doesn't get clobbered by our pushbot deploy script.
  Furthermore, umask the key to 600, so that we can override it.

- Add some more helpful information to the Pushbot commit messages,
  including what branch/PR the build was for, and a link to the
  relevant GitHub page.

- Have Travis spoof the author and email of the original committer,
  so that Travis sends the build notification message to the right place.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>