fix reflection merges

options[:conditions] is nil

also fixes for rails 4.2

refs #CNVS-26056

Change-Id: Iae3b456c8b535f41f4e61528bf0d2f4233a4a2b4
Reviewed-on: https://gerrit.instructure.com/70381
Tested-by: Jenkins
Reviewed-by: Cody Cutrer <cody@instructure.com>
Product-Review: James Williams  <jamesw@instructure.com>
QA-Review: James Williams  <jamesw@instructure.com>

app/models/assignment.rb

@@ -1005,7 +1005,7 @@ class Assignment < ActiveRecord::Base
       students = group.users
         .joins(:enrollments)
         .where(:enrollments => { :course_id => self.context})
-        .where(Course.reflections[:student_enrollments].options[:conditions])
+        .merge(Course.instance_exec(&Course.reflections[CANVAS_RAILS4_0 ? :student_enrollments : 'student_enrollments'].scope).only(:where))
         .order("users.id") # this helps with preventing deadlock with other things that touch lots of users
         .uniq
         .to_a

app/models/user.rb

@@ -2159,7 +2159,7 @@ class User < ActiveRecord::Base
 
       group_rows = pluck_global_id_rows(
           GroupMembership.joins(:group).
-              where(User.reflections[:current_group_memberships].options[:conditions]).
+              merge(User.instance_exec(&User.reflections[CANVAS_RAILS4_0 ? :current_group_memberships : 'current_group_memberships'].scope).only(:where)).
               where(user_id: users).
               select([:user_id, :group_id]).
               uniq)