message: avoid warning on first build
diff: @@ -57,7 +57,12 @@ module.exports = class BroccoliConnector {
  });
  }
  async buildSucceeded({ directory }) {
  - let nonce = parseInt(await readFile(path.join(directory, '.cardstack-build'), 'utf8'));
  + let nonce;
  + try {
  + nonce = parseInt(await readFile(path.join(directory, '.cardstack-build'), 'utf8'));
  + } catch (err) {
  + nonce = -1;
  + }
  let remaining = [];
  for (let build of this._pendingBuilds) {
  if (build.nonce <= nonce) {
  