make test: clean ext binaries when doing test-wipe

Change-Id: I9f5212ee670ea91c6b35f1406c256d0687b9c6b5
Signed-off-by: Klement Sekera <ksekera@cisco.com>
diff --git a/test/Makefile b/test/Makefile
index 132ebee..721ec96 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -140,6 +140,7 @@
 	@mkdir $(VPP_TEST_FAILED_DIR)
 
 wipe: reset
+	@make -C ext clean
 	@rm -rf $(PYTHON_VENV_PATH)
 	@rm -f $(PAPI_INSTALL_FLAGS)