Currently, the version is set in the POM (maven), but also in conf/JGROUPS_VERSION.properties. This is cumbersome, as we have to update both files on a release (and change the version back to XXX-SNAPSHOT after the release).

With the introduction of maven release-plugin, modifying the file is manual work that's unwanted.

Therefore get rid of JGROUPS-VERSION.properties and read the version directly from the POM.