Title: Views: Fixed datasource KeyError exception
Level: 1
Component: multisite
Compatible: compat
Version: 1.2.8p18
Date: 1487928038
Class: fix

When e.g. a Event Console related view was added to a dashboard and
then the Event Console was disabled or that site, this could lead
into a KeyError exception when rendering the dashboard, because the
datasource was not existant anymore.
