Launcher: Properly mute the voice recognition beep

This patch fixes the stream that remained muted even when the
launcher was paused

Change-Id: I72af6bc4da6be216e2727e69c14c5efb23b38294
Merge branch 'android-4.4' of https://github.com/omnirom/android_packages_apps_Launcher3 into kk4.4