Merge tag 'android-6.0.0_r26' into HEAD

Android 6.0.0 release 26

* tag 'android-6.0.0_r26':
  Catch exception for ConnectivityManager.unregisterNetworkCallback
  Default MMS proxy port to 80 and don't skip if port is invalid
  MMS proxy host dns lookup should happen on mms network

Change-Id: I92a2b7e802fab7dc94fd6bca01ecd5bfbb31f9d0