Made context take priority over context processors.

This is the expected behavior, but given RequestContext's tortuous
implementation, a straightforward use of its API results in the
opposite.

This commits fixes a regression that must have happened at different
points in the multiple templates engine refactor for different features.

django/template/backends/django.py

@@ -45,5 +45,11 @@ class Template(object):
             if request is None:
                 context = Context(context)
             else:
-                context = RequestContext(request, context)
+                # The following pattern is required to ensure values from
+                # context override those from template context processors.
+                original_context = context
+                context = RequestContext(request)
+                if original_context:
+                    context.push(original_context)
+
         return self.template.render(context)