Relax null parameter enforcement for legacy apps
Relax null parameter enforcement for legacy apps

No longer throws when calling cancel() with a null PendingIntent if
the app targets SDK < NYC.

Bug 25798631

Change-Id: Ic91f42808811645b01802abcc785f4218aac0e8b

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