spec: fix redis job specs in rails3

This class doesn't rely on ActiveRecord::Base in rails3, and the ==
method needed to be a bit smarter.

Change-Id: I64fc2b58fc29ebb85772567634c5ea3c4c41b9fb
Reviewed-on: https://gerrit.instructure.com/33754
Reviewed-by: James Williams  <jamesw@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: James Williams  <jamesw@instructure.com>
QA-Review: James Williams  <jamesw@instructure.com>