get dashboard loading with use_qualified_names

refs CNVS-21900, CNVS-21901

test plan:
 * in database.yml, set
     use_qualified_names: true
     schema_search_path: pg_catalog
     shard_name: public
   (probably public; adjust as necessary)
 * you should be able to login and view your dashboard without
   any 500 errors

Change-Id: I6f5bc538dcae25a7f57425411648800fbc5bd259
Reviewed-on: https://gerrit.instructure.com/58528
Tested-by: Jenkins
Reviewed-by: Rob Orton <rob@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>

app/models/account.rb

@@ -646,9 +646,9 @@ class Account < ActiveRecord::Base
       chain = Shard.shard_for(starting_account_id).activate do
         Account.find_by_sql(<<-SQL)
               WITH RECURSIVE t AS (
-                SELECT * FROM accounts WHERE id=#{Shard.local_id_for(starting_account_id).first}
+                SELECT * FROM #{Account.quoted_table_name} WHERE id=#{Shard.local_id_for(starting_account_id).first}
                 UNION
-                SELECT accounts.* FROM accounts INNER JOIN t ON accounts.id=t.parent_account_id
+                SELECT accounts.* FROM #{Account.quoted_table_name} INNER JOIN t ON accounts.id=t.parent_account_id
               )
               SELECT * FROM t
         SQL

app/models/assignment.rb

@@ -1709,8 +1709,10 @@ class Assignment < ActiveRecord::Base
   }
 
   scope :not_ignored_by, lambda { |user, purpose|
-    where("NOT EXISTS (SELECT * FROM ignores WHERE asset_type='Assignment' AND asset_id=assignments.id AND user_id=? AND purpose=?)",
+    where("NOT EXISTS (?)",
-          user, purpose)
+          Ignore.where(asset_type: 'Assignment',
+                       user_id: user,
+                       purpose: purpose).where('asset_id=assignments.id'))
   }
 
   # the map on the API_NEEDED_FIELDS here is because PostgreSQL will see the

app/models/user.rb

@@ -1875,7 +1875,7 @@ class User < ActiveRecord::Base
     self.shard.activate do
       Shackles.activate(:slave) do
         visible_instances = visible_stream_item_instances(opts).
-            includes(:stream_item => :context).
+            preload(stream_item: :context).
             limit(Setting.get('recent_stream_item_limit', 100))
         visible_instances.map do |sii|
           si = sii.stream_item