`self.log.deprecated` checks against EasyBuild version, not Lmod version

I added a block that throws an error when the Lmod version we require is v5.1.5 or higher. This will pop up during test (e.g. via https://jenkins1.ugent.be/view/EasyBuild/job/easybuild-framework_unit-test_hpcugent_develop-lmod/).