fix has_annotations?

fixes: GRADE-339

test plan:
  - with new annotations disabled
  - have a course with an assignment that requires a file upload
  - have a student submit the assignment with a doc pdf or docx file
    type
  - as the student or teacher go to the assignment submissions page
  - as a student click 'Grades'
  - click the assignment that was previously submitted
  - ensure that the document preview loads without errors
  - as a teacher click 'Grades'
  - click the students name
  - click the assignment that was previously submitted
  - ensure that the document preview loads without errors

Change-Id: Idd6984aae779205b247927843da8c8acfb5a33d6
Reviewed-on: https://gerrit.instructure.com/128803
Reviewed-by: Spencer Olson <solson@instructure.com>
Reviewed-by: Keith T. Garner <kgarner@instructure.com>
Tested-by: Jenkins
QA-Review: KC Naegle <knaegle@instructure.com>
Product-Review: Keith T. Garner <kgarner@instructure.com>

app/models/canvadoc.rb

@@ -61,7 +61,7 @@ class Canvadoc < ActiveRecord::Base
     account_context = attachment.context.try(:account)
     account_context ||= attachment.context.try(:root_account)
     new_annotations_enabled = account_context&.feature_enabled?(:new_annotations)
-    new_annotations_enabled || annotations == true
+    new_annotations_enabled || has_annotations == true
   end
 
   def self.mime_types

spec/models/canvadoc_spec.rb

@@ -121,4 +121,16 @@ describe 'Canvadoc' do
       expect(@doc).not_to be_available
     end
   end
+
+  describe "#has_annotations?" do
+    it "has annotations when true and new annotations are not enabled" do
+      @doc.has_annotations = true
+      expect(@doc).to have_annotations
+    end
+
+    it "does not have annotations when false and new annotations are not enabled" do
+      @doc.has_annotations = false
+      expect(@doc).not_to have_annotations
+    end
+  end
 end