fix web conference user settings for rails 3

Change-Id: I77aebfc4626971bc113e440f6a9639574c91423b
Reviewed-on: https://gerrit.instructure.com/29471
Reviewed-by: Cody Cutrer <cody@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: James Williams  <jamesw@instructure.com>
QA-Review: James Williams  <jamesw@instructure.com>