No beep for sticky, slow, and bounce keys features

[Luca Ferretti]

It seems there is no audio feedback (beep) to assist in typing with a11y features enabled. The audio file to play ("bell" named sound) is installed (both ubuntu and freedesktop sound themes).

## Steps to reproduce
 1) Open System Settings > Universal Access
 2) Go to Typing tab
 3) Turn ON Slow Keys switch
 4) Activate "Beep when a key is ... accepted"
 5) Focus test text entry and press (and hold) a key on keyboard

## Expected result
 The systems should beep when the key press is accepted and the letter appears on screen

## Current result
 No sound

## Additional info
*Same issue for other beep related options in Styky, Slow and Bound keys.
* It seems a Ubuntu only issue, 'cause the same feature in Fedora 17 works fine (and it seems there are no special differences between Fedora's and Ubuntu's a11y/sound related values for GSettings keys).
* Release: 12.04
* Package version: 3.4.1-0ubuntu1.1

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: gnome-settings-daemon 3.4.1-0ubuntu1.1
ProcVersionSignature: Ubuntu 3.2.0-24.37-generic 3.2.14
Uname: Linux 3.2.0-24-generic x86_64
ApportVersion: 2.0.1-0ubuntu7
Architecture: amd64
Date: Sat May 19 01:08:18 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64 (20120327.1)
SourcePackage: gnome-settings-daemon
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.