NPE reported in 1.509.3 from OldDataMonitor as part of a general startup failure.
In this case display the reported exceptions differently and be done with it.
java.lang.NullPointerException
	at hudson.diagnosis.OldDataMonitor.report(OldDataMonitor.java:178)
	at hudson.util.RobustReflectionConverter.doUnmarshal(RobustReflectionConverter.java:312)
	at hudson.util.RobustReflectionConverter.unmarshal(RobustReflectionConverter.java:222)
	at com.thoughtworks.xstream.core.TreeUnmarshaller.convert(TreeUnmarshaller.java:72)