bulk update requests: fix reference to title attribute.

Also remove non-nullable and default options from migration. The column
didn't originally have these options so they shouldn't be added if the
migration is reverted.

app/views/bulk_update_requests/show.html.erb

@@ -1,6 +1,6 @@
 <div id="c-bulk-update-requests">
   <div id="a-show">
-    <h1>Bulk Update Request: <%= @bulk_update_request.title %></h1>
+    <h1>Bulk Update Request</h1>
 
     <ul>
       <% if @bulk_update_request.forum_topic_id %>

db/migrate/20200318224633_drop_title_from_bulk_update_requests.rb

@@ -1,5 +1,5 @@
 class DropTitleFromBulkUpdateRequests < ActiveRecord::Migration[6.0]
   def change
-    remove_column :bulk_update_requests, :title, :text, null: false, default: ""
+    remove_column :bulk_update_requests, :title, :text
   end
 end

test/functional/bulk_update_requests_controller_test.rb

@@ -44,6 +44,13 @@ class BulkUpdateRequestsControllerTest < ActionDispatch::IntegrationTest
       end
     end
 
+    context "#show" do
+      should "render" do
+        get bulk_update_request_path(@bulk_update_request)
+        assert_response :success
+      end
+    end
+
     context "#destroy" do
       context "for the creator" do
         should "succeed" do