Update publish scripts

Author: jshcrowthe

package.json

@@ -18,7 +18,8 @@
     "dev": "lerna run --parallel --scope @firebase/* --scope firebase dev",
     "prepare": "lerna run --scope @firebase/* --scope firebase prepare",
     "prepush": "node tools/gitHooks/prepush.js",
-    "publish:packages": "lerna publish --scope @firebase/* --scope firebase --registry http://localhost:4873",
+    "prepublish:packages": "lerna publish --scope @firebase/* --scope firebase --skip-npm",
+    "publish:packages": "lerna exec -- npm publish",
     "repl": "node tools/repl.js",
     "pretest": "node tools/pretest.js",
     "test": "lerna run --parallel test",