Deprecate old embargo implementation.

The new "country access" implementation replaces the old
implementation.  Middleware and tests have been updated
accordingly, but deprecated models are preserved
for backwards compatibility.

cms/urls.py

@@ -60,7 +60,6 @@ urlpatterns += patterns(
     # ajax view that actually does the work
     url(r'^login_post$', 'student.views.login_user', name='login_post'),
     url(r'^logout$', 'student.views.logout_user', name='logout'),
-    url(r'^embargo$', 'student.views.embargo', name="embargo"),
 )
 
 # restful api