Fixing bug in forced vagrant destroy action

Change-Id: I30a8bd44478c63916e39e2e093df9894c328d1d8
diff --git a/Makefile b/Makefile
index daaa435..8c9ec88 100644
--- a/Makefile
+++ b/Makefile
@@ -135,7 +135,7 @@
 	$(ANSIBLE_PB) $(PI)/bootstrap-dev-env.yml $(LOGCMD)
 
 vagrant-destroy:
-	$(VAGRANT) -f destroy $(LOGCMD)
+	$(VAGRANT) destroy -f $(LOGCMD)
 	rm -f $(M)/vagrant-up
 
 xos-teardown: xos-update-images