format fix: passing a negative width to %*d should pad to the left (Benoît Vaugon)

git-svn-id: http://caml.inria.fr/svn/ocaml/version/4.02@15271 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
camlinternalFormat.ml: minor style fixes (Benoît Vaugon)

git-svn-id: http://caml.inria.fr/svn/ocaml/version/4.02@15272 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02