follow-up to commit 15306

git-svn-id: http://caml.inria.fr/svn/ocaml/version/4.02@15312 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
testsuite: fix small mistake in makefile

git-svn-id: http://caml.inria.fr/svn/ocaml/version/4.02@15313 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02