avoid dynamic finders on an assocition with an include

the dynamic finder on the association causes scoping to be called
before delegating the dynamic finder to the class, which works
until the preloader tries to load the owning class, and BOOM,
tries to preload itself

fixes at least one spec for rails 3

Change-Id: Ia22b31a013cb6ac984eb77ca29406372538ea57f
Reviewed-on: https://gerrit.instructure.com/30393
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>

app/models/context_module_item.rb

@@ -47,7 +47,7 @@ module ContextModuleItem
     preferred_id = preferred_id[Api::ID_REGEX] if preferred_id.is_a?(String)
     objs_to_search.each do |obj|
       next unless obj.present?
-      tag = obj.context_module_tags.find_by_id(preferred_id)
+      tag = obj.context_module_tags.where(:id => preferred_id).first
       return tag if tag
     end
     objs_to_search.each do |obj|

app/models/wiki_page.rb

@@ -257,7 +257,7 @@ class WikiPage < ActiveRecord::Base
   end
 
   def context_module_tag_for(context)
-    @tag ||= self.context_module_tags.find_by_context_id_and_context_type(context.id, context.class.to_s)
+    @tag ||= self.context_module_tags.where(context_id: context, context_type: context.class.base_ar_class.name).first
   end
 
   def context_module_action(user, context, action)

lib/imported_html_converter.rb

@@ -56,7 +56,7 @@ class ImportedHtmlConverter
               end
             end
           elsif val =~ %r{\$CANVAS_COURSE_REFERENCE\$/modules/items/(.*)}
-            if tag = context.context_module_tags.find_by_migration_id($1, :select => 'id')
+            if tag = context.context_module_tags.where(:migration_id => $1).select('id').first
               new_url = URI::escape "#{course_path}/modules/items/#{tag.id}"
             end
           elsif val =~ %r{(?:\$CANVAS_OBJECT_REFERENCE\$|\$WIKI_REFERENCE\$)/([^/]*)/(.*)}