up-to-date BK changelog instead of sql/ChangeLog, add LICENSE if
   available)


scripts/make_binary_distribution.sh:
   - Don't include sql/ChangeLog in the binary distribution (it's not
     updated anymore since we've moved to BK)
   - Include the BK ChangeLog from top level directory instead, if it exists
   - also add the LICENSE file to the binary distribution, if it exists
     (required for the non-GPL builds)