title: django middware only "process_response" when miss trailing slash
body: <p>i've write a middware like this:</p>
  
  <pre><code>class LogMiddleware( object ):
  
      def process_request( self, request ):
          logging.debug("start")
  
      def process_response( self, request, response ):
          logging.debug("end")
          return response
  </code></pre>
  
  <p>and I put it in the bottom of MIDDLEWARE_CLASSES</p>
  
  <p>most time it works fine.</p>
  
  <p>and when I test with url /admin  without an trailing "/"  and I could only see the "end" logged, why?</p>