buildserver: disable flutter dev/build analytics globally

The Flutter dev tools includes opt-out analytics, with a config option to
opt out.  We can at least try to disable them in the buildserver. That
config option is unfortunately not even guaranteed to work:
https://github.com/flutter/flutter/issues/19304
https://github.com/flutter/flutter/issues/45369

issuebot#21
issuebot!49
https://github.com/flutter/flutter/issues/73657

buildserver/Vagrantfile

@@ -86,6 +86,7 @@ Vagrant.configure("2") do |config|
   config.vm.provision "shell", name: "android-ndk", path: "provision-android-ndk",
     args: ["/opt/android-sdk/ndk", "r21e", "r23b"]
   config.vm.provision "shell", name: "gradle", path: "provision-gradle"
+  config.vm.provision "shell", name: "disable-analytics", path: "provision-disable-analytics"
   config.vm.provision "shell", name: "buildserverid", path: "provision-buildserverid",
     args: [`git rev-parse HEAD`]
 

buildserver/provision-disable-analytics

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+set -ex
+
+# Flutter
+# https://github.com/flutter/flutter/issues/73657
+flutter_conf=/home/vagrant/.flutter
+cat <<EOF > $flutter_conf
+{
+  "enabled": false
+}
+EOF
+chown -R vagrant.vagrant $flutter_conf
+chmod -R 0644 $flutter_conf
+