Only check if Rails responds to assets.

- Rails.application.assets can apparently be nil at boot time (Rails
  3.2.14). We still want to use asset pipeline in this case.

lib/jasmine/dependencies.rb

@@ -23,7 +23,7 @@ def legacy_rack?
       end
 
       def use_asset_pipeline?
-        (rails3? || rails4?) && Rails.respond_to?(:application) && Rails.application.respond_to?(:assets) && Rails.application.assets
+        (rails3? || rails4?) && Rails.respond_to?(:application) && Rails.application.respond_to?(:assets)
       end
 
       private