Fixed some warnings flagged by IAR C-STAT static analysis tool.

bacnet-stack/demo/handler/h_wp.c

@@ -136,13 +136,11 @@ void handler_write_property(
     bytes_sent =
         datalink_send_pdu(src, &npdu_data, &Handler_Transmit_Buffer[0],
         pdu_len);
-#if PRINT_ENABLED
     if (bytes_sent <= 0) {
+#if PRINT_ENABLED
         fprintf(stderr, "WP: Failed to send PDU (%s)!\n", strerror(errno));
-    }
-#else
-    bytes_sent = bytes_sent;
 #endif
+    }
 
     return;
 }