make sure that we do not call coll_gather and coll_bcast in the very same
instances, since some collective (intra) modules do not seem to like the fact
if they are called for scount or rcount being zero (for regular
intra-communicator operations, this is handled on the MPI API layer).
Fixes trac:2405
This commit was SVN r23188.
The following Trac tickets were found above:
Ticket 2405 --> https://svn.open-mpi.org/trac/ompi/ticket/2405