io/ompio: fix the reference count of basic datatypes used as etypes or ftypes.

ompi/mca/common/ompio/common_ompio_file_view.c

@@ -32,6 +32,7 @@ static int datatype_duplicate  (ompi_datatype_t *oldtype, ompi_datatype_t **newt
 {
     ompi_datatype_t *type;
     if( ompi_datatype_is_predefined(oldtype) ) {
+	OBJ_RETAIN(oldtype);
         *newtype = oldtype;
         return OMPI_SUCCESS;
     }

ompi/mca/io/ompio/io_ompio_file_set_view.c

@@ -38,6 +38,7 @@ static int datatype_duplicate  (ompi_datatype_t *oldtype, ompi_datatype_t **newt
 {
     ompi_datatype_t *type;
     if( ompi_datatype_is_predefined(oldtype) ) {
+        OBJ_RETAIN(oldtype);
         *newtype = oldtype;
         return OMPI_SUCCESS;
     }