Fix a problem in packing/unpacking job updates. There remains a race condition that causes messages to attempt to be sent to the second new daemon before it is completely ready. Not entirely sure where it is coming from.
Refs #4665
Rebase to master. Reset orte_nidmap_communicated if hosts are added. Check for duplicate hostnames in an add_host command. Turn off tree_spawn for dynamic launch of additional daemons.
Signed-off-by: Ralph Castain <rhc@open-mpi.org>
