Made VoicemailContract classes non-instantiable.
Made VoicemailContract classes non-instantiable.

Change-Id: I35539e5b293412f4f11b0bc062d754f813d4168e

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