pipe2browser: Change vomtestgen and vdl tools flags from underscores to hyphens.

MultiPart: 5/6

Change-Id: I49d78df0a3a1a14aad7f43c54d1191af156fa090
diff --git a/Makefile b/Makefile
index afb6cad..2961c35 100644
--- a/Makefile
+++ b/Makefile
@@ -42,7 +42,7 @@
 	touch browser/third-party
 
 browser/services/vdl/index.js:
-	v23 run vdl generate --lang=javascript --js_out_dir=browser/services p2b/vdl
+	v23 run vdl generate --lang=javascript --js-out-dir=browser/services p2b/vdl
 
 # Bundle whole app and third-party JavaScript into a single build.js
 browser/build.js: $(JS_FILES) browser/services/vdl/index.js  browser/third-party node_modules