Rename CVSNT "mergepoints" test and make it executable. - rename test-convert-cvs-builtincvsps-cvsnt-mergepoints (and related files) to test-convert-cvsnt-mergepoints - this ensures that the test will be run, but does NOT make it pass: in particularly, it fails regularly for me due to the inconsistent behaviour of CVS itself - expect "Branchpoints:" in debugcvsps output