Use request.COOKIES to activate the timezone

This patch fixes the inconsistency in the instance
creation time.

Change-Id: Ic4afd9a03f0278883e0d00a2e075acaa4b4f8dc1
Co-Authored-By: bhavani <bhavani.r@nectechnologies.in>
Closes-Bug: #1418031
(cherry picked from commit 29a3768379)

horizon/middleware/base.py

@@ -106,7 +106,7 @@ class HorizonMiddleware(object):
                         }
                     )
 
-        tz = request.session.get('django_timezone')
+        tz = utils.get_timezone(request)
         if tz:
             timezone.activate(tz)