ATLINFR-4168: Update KLFitter to version 1.4.0
This updates KLFitter to version 1.4.0, which contains a new likelihood for reconstructing a single top quark as well as a minor fix of a missing include that became apparent with more recent ROOT versions. No larger hick-ups in terms of builds should be expected.
Placement of the tarball to eos requested in ATLINFR-4168.