mark the "self" peer OMPI_OSC_RDMA_PEER_LOCAL_BASE when
the window is dynamically created and use_cpu_atomics is set
in order to correctly handle communications to self.
Thanks Bart Janssens for reporting this issue.
Refs. open-mpi/ompi#6394
Signed-off-by: Gilles Gouaillardet <gilles@rist.or.jp>