fix a segfault in the two-phase I/O algorithm for fileviews of 0 byte size.

ompi/mca/fcoll/two_phase/fcoll_two_phase_file_write_all.c

@@ -314,8 +314,14 @@ mca_fcoll_two_phase_file_write_all (mca_io_ompio_file_t *fh,
 	flat_buf->count = local_size;
 	i=0;j=0;
 	while(j < local_size){
-	    flat_buf->indices[j] = (OMPI_MPI_OFFSET_TYPE)(intptr_t)decoded_iov[i].iov_base;
+	    if ( 0 < max_data  ) {
-	    flat_buf->blocklens[j] = decoded_iov[i].iov_len;
+		flat_buf->indices[j] = (OMPI_MPI_OFFSET_TYPE)(intptr_t)decoded_iov[i].iov_base;
+		flat_buf->blocklens[j] = decoded_iov[i].iov_len;
+	    }
+	    else {
+		flat_buf->indices[j] = 0;
+		flat_buf->blocklens[j] = 0;
+	    }
 	    if(i < (int)iov_count)
 		i+=1;
 	    j+=1;