Change "Simple" to "Response"

The plan has changed since when we originally envisioned it.
"Response" is a better name for it than "Simple" which isn't a
noun and is harder to talk about.
Handle ElasticHttpError in dashboard

If the index doesn't exist or the mapping type is wrong, then
pyelasticsearch kicks up an ElasticHttpError. This picks up the fix
in elasticutils that handles that in the es_required_or_50x decorator.
Fix bad test

This fixes a test that was always returning true despite the fact that
one of the cases fails. This fixes the test, but one case still fails.