AV::logger returns AC::logger if it's defined, workaround meanwhile AV doesn't have it's own logger

Signed-off-by: NJosé Valim <jose.valim@gmail.com>

actionpack/lib/action_view/log_subscriber.rb

@@ -12,8 +12,9 @@ def render_template(event)
     alias :render_partial :render_template
     alias :render_collection :render_template
 
+    # TODO: Ideally, ActionView should have its own logger so it does not depend on AC.logger
     def logger
-      ActionController::Base.logger
+      ActionController::Base.logger if defined?(ActionController::Base)
     end
 
   protected
@@ -24,4 +25,4 @@ def from_rails_root(string)
   end
 end
 
-ActionView::LogSubscriber.attach_to :action_view
\ No newline at end of file
+ActionView::LogSubscriber.attach_to :action_view