make sure ajax prefilters are applied early

instructure.js is not guaranteed to be loaded and executed before
page-specific bundles have started executing. it would be bad to
accidentally make a JSON API request without the appropriate Accept, or
any request without the appropriate CSRF protection.

jquery.instructure_jquery_patches.js is guaranteed to load first as part
of the common bundle.

Change-Id: I8813d04611eca62fe7f71e4245f43d73d266efd0
Reviewed-on: https://gerrit.instructure.com/31853
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Simon Williams <simon@instructure.com>
Reviewed-by: Aaron Shafovaloff <ashafovaloff@instructure.com>
Reviewed-by: Jacob Fugal <jacob@instructure.com>
Product-Review: Jacob Fugal <jacob@instructure.com>
QA-Review: Jacob Fugal <jacob@instructure.com>