clear mini profiler cookie when admin logs off

lib/auth/default_current_user_provider.rb

@@ -90,6 +90,12 @@ class Auth::DefaultCurrentUserProvider
     if SiteSetting.log_out_strict && (user = current_user)
       user.auth_token = nil
       user.save!
+
+      if user.admin && defined?(Rack::MiniProfiler)
+        # clear the profiling cookie to keep stuff tidy
+        cookies["__profilin"] = nil
+      end
+
       MessageBus.publish "/logout", user.id, user_ids: [user.id]
     end
     cookies[TOKEN_COOKIE] = nil