services: change default sampling interval to -1

Change default sampling interval to -1 to avoid sampling to resolve
power consumption issue. Original implement will keep UE wake up every
12 minutes, which will cause issue when doing power standby test.

Change-Id: I018e22a44259e94bce87ceaf04ff523f035183f8

Conflicts:
	services/java/com/android/server/ConnectivityService.java