Made it compatible > 1.9 (celery#557)

* Made it compatible > 1.9

See https://docs.djangoproject.com/en/1.9/releases/1.8/#deprecated-features-1-8

* Update admin.py

forgot imports

Author: arrahimi2

djcelery/admin.py

@@ -8,8 +8,7 @@
 from django.contrib.admin import helpers
 from django.contrib.admin.views import main as main_views
 from django.forms.widgets import Select
-from django.shortcuts import render_to_response
-from django.template import RequestContext
+from django.shortcuts import render
 from django.utils.html import escape, format_html, mark_safe
 from django.utils.translation import ugettext_lazy as _
 
@@ -199,10 +198,7 @@ def rate_limit_tasks(self, request, queryset):
             'app_label': app_label,
         }
 
-        return render_to_response(
-            self.rate_limit_confirmation_template, context,
-            context_instance=RequestContext(request),
-        )
+        return render(request, self.rate_limit_confirmation_template, context)
 
     def get_actions(self, request):
         actions = super(TaskMonitor, self).get_actions(request)