Move flash messages CSS to app.

Author: arkirchner

app/assets/stylesheets/application.css

@@ -10,10 +10,6 @@
  * files in this directory. Styles in this file should be added after the last require_* statement.
  * It is generally better to create a new file per style scope.
  *
- * lib/assets
- *= require flash
- *
- * app/assets
  *= require_tree .
  *= require_self
  */