Better workaround for beta3

Author: Sam Phippen

example_app_generator/generate_action_mailer_specs.rb

@@ -13,6 +13,7 @@ def comment_lines(path, flag, *args)
   comment_lines 'config/environments/test.rb', /action_mailer/
 
   initializer 'action_mailer.rb', <<-CODE
+  require "action_view/base"
     if ENV['DEFAULT_URL']
       if ::Rails::VERSION::STRING < '4.1'
         ExampleApp::Application.configure do