Eli, I am not sure what you meant by is not hard-coded? This is the project's version definition (one of the core Maven properties) much like the one in build.xml
<property name="version" value="0.23.0-SNAPSHOT"/>
While I agree that adding 6th entry of the same version string to the build system isn't a very bright thing to do, but I don't believe it should be taken care off in this particular JIRA - it rather be better done as a part of mavenization project. Besides, I am afraid Maven won't be able to use the one from Ant build system.
As for testing, I have ran maven sonar:sonar with the test in place on a system running sonar system and was able to see all kinds of statistics about HDFS code base.