Fix typo causing NullPointerException

Fixes a NPE I was seeing with the following stack:
Exception in thread "main" java.lang.NullPointerException
	at crosby.binary.OsmInfoReader.hasValidUserId(OsmInfoReader.java:28)
	at crosby.binary.OsmObjectFactory.createOsmInfo(OsmObjectFactory.java:62)
	at crosby.binary.OsmObjectFactory.createWay(OsmObjectFactory.java:145)
	at org.osmtools.pbf.OsmPbfParser.parseWays(OsmPbfParser.java:34)
	at crosby.binary.BinaryParser.parse(BinaryParser.java:67)
        ...