MPI_Ialltoallw() and friends take a const MPI_Datatype types[] argument.
In order to be able to call OBJ_RELEASE(types[0]), we used to simply
drop the const modifier. This change make it right by introducing the
OBJ_RELEASE_NO_NULLIFY(object) macro that no more set object = NULL
if the object is freed.
Signed-off-by: Gilles Gouaillardet <gilles@rist.or.jp>
c49e5e5c4a