Update middleware to new style classes

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/common/middleware/error_logging.py

@@ -4,11 +4,12 @@ import logging
 
 from django.core.exceptions import PermissionDenied
 from django.http import Http404
+from django.utils.deprecation import MiddlewareMixin
 
 logger = logging.getLogger(__name__)
 
 
-class ErrorLoggingMiddleware(object):
+class ErrorLoggingMiddleware(MiddlewareMixin):
     def process_exception(self, request, exception):
         if not isinstance(exception, (PermissionDenied, Http404)):
             # Don't log non critical exceptions