Start tether service with redeliver intent

So that the intent comes back when we are restarted rather than
null causing a crash.

Bug: 23678853
Change-Id: I1697159d5557feb7a87b238f8efa99ed3142fe6a

src/com/android/settings/TetherService.java

@@ -125,7 +125,7 @@ public class TetherService extends Service {
         }
         // We want to be started if we are killed accidently, so that we can be sure we finish
         // the check.
-        return START_STICKY;
+        return START_REDELIVER_INTENT;
     }
 
     @Override