title: Log4Net config in external file does not work
body: <p>We are using log4net and want to specify it's configuration in an external config file (as we have done with other sections). To do this we have changed the log4net section in the App.config to:</p>
  
  <pre class="lang-xml prettyprint-override"><code>...
  &lt;section name="log4net" 
       type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/&gt;
  ...
  &lt;log4net configSource="Log.config" /&gt;
  ...
  </code></pre>
  
  <p>And in the Log.Config file (same directory as the App.config) we have:</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;log4net&gt;
    &lt;appender name="General" type="log4net.Appender.FileAppender"&gt;
      &lt;file value="myapp.log" /&gt;
      &lt;layout type="log4net.Layout.SimpleLayout" /&gt;
    &lt;/appender&gt;
    &lt;root&gt;
      &lt;appender-ref ref="General" /&gt;
    &lt;/root&gt;
  &lt;/log4net&gt;
  </code></pre>
  
  <p>However, when we run the app, no log file is created (and no logging done). There are no error messages output to the console.</p>
  
  <p>If we move the contents of the Log.config file back into the App.config (replacing the first code line above), it works as expected. Any idea why it is not working in an external file?</p>