Rethink AWS credentials script

[waldoj]

It's being run in Travis CI, but the deploy process doesn't transfer it off the machine. So it's doing no good. Figure out a functional way to do this.

[waldoj]

On reflection, the obvious thing to do is to store the credentials files in the repo root, as Travis output, and then move it into ~/.aws/, on deployment. However, be extraordinarily careful never to allow this file to enter a webroot.