message: Always use fluid container for navbar.
  As in removes the
  final non fluid container navbar, I think there's no need to keep this
  line of code. Just use navbar with fluid container, always.
diff: {% set WARNING_MSG = appbuilder.app.config.get('WARNING_MSG') %}
  <div class="navbar navbar-static-top {{menu.extra_classes}}" role="navigation">
  - <div class="container{{ '-fluid' if not navbar_container else '' }}">
  + <div class="container-fluid">
  <div class="navbar-header">
  <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
  <span class="icon-bar"></span>
  