message: Fix polyserve->polymer-build dependency
diff: "mz": "^2.4.0",
  "opn": "^3.0.2",
  "pem": "^1.8.3",
  - "polymer-build": "3.0.0-pre.10",
  + "polymer-build": "^3.0.0-pre.10",
  "requirejs": "^2.3.4",
  "resolve": "^1.5.0",
  "send": "^0.14.1",
  