The integration tests needs /usr/bin/diff, so require diffutils
Cover RPM file digests in the integration tests
TODO cleanup
cxxll::java_class: New member functions major_version(), minor_version()
SQL schema: Add columns major_version, minor_version to symboldb.java_class

Adjust loading code accordingly.
Move Java reference, field and method definition to integration tests
Increase Java class test coverage in the integration test