Patch from Gilles Gouaillardet on #4506 to correctly handle 0-sized
messages in coll/basic MPI_Alltoallv and MPI_Alltoallw.
Reviewed by Jeff Squyres.
Fixes trac:4506.
cmr=v1.8.2:reviewer=ompi-rm1.8
This commit was SVN r31519.
The following Trac tickets were found above:
Ticket 4506 --> https://svn.open-mpi.org/trac/ompi/ticket/4506