LOG4NET-354 reverted changes from revision 1489736 since we do not want to change the public API

However, there should be an entry in the FAQ that explains the usage of LogManager.GetRepository().Configured
which still needs to be written.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4net/trunk@1491695 13f79535-47bb-0310-9956-ffa450edef68