Fix rendering for config form JS models

Review Request #8082 — Created March 28, 2016 and submitted — Latest diff uploaded

Information

Djblets
release-0.8.x

Reviewers

The JS model for a JS view for a config form was previously rendering
incorrectly (without a trailing )). This issue has been addressed.
Also, we now are more careful to only render a trailing comma after the
JS model data if there is in fact a page-wide config object. This object
is now only added to the models if it exists.

Tested this with Review Board. The generated JS works now.