Merge pull request #10637 from hppritcha/fix_for_issue_10576

sessions: switch to mpi_size for info key

Author: hppritcha

ompi/include/mpi.h.in

@@ -1381,7 +1381,7 @@ OMPI_DECLSPEC extern struct ompi_predefined_datatype_t ompi_mpi_ub;
 /*
  * Predefined info keys
  */
-#define MPI_INFO_KEY_SESSION_PSET_SIZE  "size"
+#define MPI_INFO_KEY_SESSION_PSET_SIZE  "mpi_size"
 
 /*
  * MPI API