config parser failures should provide more useful error

I attempted to modify the config and got the following exception on controller startup:

2013-12-03 05:44:40.535 PST [ConfigPersister-registrator] ERROR o.o.c.l.b.i.UncaughtExceptionHandler - Uncaught ExceptionHandler:
java.lang.IllegalStateException: Unable to load last config
at org.opendaylight.controller.netconf.persist.impl.ConfigPersisterNotificationHandler.pushLastConfigWithRetries(ConfigPersisterNotificationHandler.java:132) ~[na:na]
at org.opendaylight.controller.netconf.persist.impl.ConfigPersisterNotificationHandler.init(ConfigPersisterNotificationHandler.java:104) ~[na:na]
at org.opendaylight.controller.netconf.persist.impl.osgi.ConfigPersisterActivator$1.run(ConfigPersisterActivator.java:65) ~[na:na]
at java.lang.Thread.run(Thread.java:724) ~[na:1.7.0_25]
Caused by: org.xml.sax.SAXParseException: The element type "data" must be terminated by the matching end-tag "</data>".
at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:251) ~[na:1.7.0_25]
at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:300) ~[na:1.7.0_25]
at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:121) ~[na:1.7.0_25]
at org.opendaylight.controller.netconf.util.xml.XmlUtil.readXmlToDocument(XmlUtil.java:70) ~[na:na]
at org.opendaylight.controller.netconf.util.xml.XmlUtil.readXmlToDocument(XmlUtil.java:59) ~[na:na]
at org.opendaylight.controller.netconf.util.xml.XmlUtil.readXmlToElement(XmlUtil.java:49) ~[na:na]
at org.opendaylight.controller.netconf.persist.impl.ConfigPersisterNotificationHandler.pushLastConfigWithRetries(ConfigPersisterNotificationHandler.java:125) ~[na:na]
... 3 common frames omitted

I'm not saying I got the config right... but the error should be more helpful and point to a line where the issue is.