update graphsettings with this.change
update graphsettings with this.change

Test Plan:
change some settings before and after this change, and
make sure the result is the same (including invalidation message)

Reviewers: alex

Reviewed By: alex

Subscribers: alpert

Differential Revision: http://phabricator.khanacademy.org/D7424

chirilo/perseus,junyiacademy/perseus,daukantas/perseus,daukantas/perseus,ariabuckles/perseus,huangins/perseus,chirilo/perseus,alexristich/perseus,learningequality/perseus,abe4mvp/perseus,ariabuckles/perseus,abe4mvp/perseus,iamchenxin/perseus,learningequality/perseus,huangins/perseus,sachgits/perseus,sachgits/perseus,junyiacademy/perseus,iamchenxin/perseus,alexristich/perseus,ariabuckles/perseus,ariabuckles/perseus