Comment 2 for bug 1426418

I've reproduced this on vivid proposed build 114 as well. I've confirmed the setting is changing in accountsservice, but still getting the beep from push notifications.

gdbus introspect --system -d org.freedesktop.Accounts -o /org/freedesktop/Accounts/User`id -u phablet`|grep -A21 com.ubuntu.touch.AccountsService.Sound
  interface com.ubuntu.touch.AccountsService.Sound {
    methods:
    signals:
    properties:
      @org.freedesktop.Accounts.DefaultValue("false")
      readwrite b SilentMode = true;
      @org.freedesktop.Accounts.DefaultValue.String("/usr/share/sounds/ubuntu/ringtones/Ubuntu.ogg")
      readwrite s IncomingCallSound = '/usr/share/sounds/ubuntu/ringtones/Ubuntu.ogg';
      @org.freedesktop.Accounts.DefaultValue.String("/usr/share/sounds/ubuntu/notifications/Xylo.ogg")
      readwrite s IncomingMessageSound = '/usr/share/sounds/ubuntu/notifications/Xylo.ogg';
      @org.freedesktop.Accounts.DefaultValue("true")
      readwrite b IncomingCallVibrate = true;
      @org.freedesktop.Accounts.DefaultValue("true")
      readwrite b IncomingCallVibrateSilentMode = true;
      @org.freedesktop.Accounts.DefaultValue("true")
      readwrite b IncomingMessageVibrate = true;
      @org.freedesktop.Accounts.DefaultValue("true")
      readwrite b IncomingMessageVibrateSilentMode = true;
      @org.freedesktop.Accounts.DefaultValue("true")
      readwrite b OtherVibrate = true;
      @org.freedesktop.Accounts.DefaultValue("true")
      readwrite b DialpadSoundsEnabled = true;