message: Update build_on_vm.sh
  Fix breakage after repo transfer
diff: @@ -130,7 +130,7 @@ gcloud compute ssh "$machine_name" -- bash << EOF
  fi
  # CentOS 6's git is old enough that git clone -b <tag> doesn't work and
  # silently checks out HEAD. To be safe we use an explicit checkout below.
  - git clone https://github.com/apache/incubator-pagespeed-mod.git
  + git clone https://github.com/apache/incubator-pagespeed-mod.git mod_pagespeed
  cd mod_pagespeed
  git checkout "$branch"
  install/build_release.sh $@
  