Avoid launching dialogs twice from double-clicking a preference.
Avoid launching dialogs twice from double-clicking a preference.

Bug: 6500628

Only create the dialog if another one doesn't already exist.

Change-Id: Ie9be06a58c369299bcb67526e668785e6735a307

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base