ErrorLogFile: Call ConsoleAppender.activateOptions()

This is required to prepare the appender for use, otherwise the
following error is printed:

log4j:ERROR No output stream or file set for the appender named [null].

Change-Id: I76734dd4c162cf4f897688599b4050514cc1c920

gerrit-pgm/src/main/java/com/google/gerrit/pgm/util/ErrorLogFile.java

@@ -45,6 +45,7 @@ public class ErrorLogFile {
     dst.setLayout(layout);
     dst.setTarget("System.err");
     dst.setThreshold(Level.ERROR);
+    dst.activateOptions();
 
     final Logger root = LogManager.getRootLogger();
     root.removeAllAppenders();