Fix IndexOutOfBoundsException while silent provisioning check

- If hostpot off, we receive result through HotspotOffReceiver.
  Sometimes, during provisioning, we're used to receive this.
  In this case, we don't care.
  After provisioning, we'll receive the intent again.

- In stress test,
  index is sometimes invalid, equals to mCurrentTethers.size().
  So, when provisioning, We check whether index is valid or not.

BUG=23528220
Change-Id: I70f35e045042c6c81b1db03e2a44cd41d3e7437f

src/com/android/settings/HotspotOffReceiver.java

@@ -5,6 +5,7 @@ import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.net.wifi.WifiManager;
+import android.util.Log;
 
 import com.android.settingslib.TetherUtil;
 
@@ -14,11 +15,15 @@ import com.android.settingslib.TetherUtil;
  */
 public class HotspotOffReceiver extends BroadcastReceiver {
 
+    private static final String TAG = "HotspotOffReceiver";
+    private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
+
     @Override
     public void onReceive(Context context, Intent intent) {
         if (WifiManager.WIFI_AP_STATE_CHANGED_ACTION.equals(intent.getAction())) {
             WifiManager wifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
             if (wifiManager.getWifiApState() == WifiManager.WIFI_AP_STATE_DISABLED) {
+                if (DEBUG) Log.d(TAG, "TetherService.cancelRecheckAlarmIfNecessary called");
                 // The hotspot has been turned off, we don't need to recheck tethering.
                 TetherService.cancelRecheckAlarmIfNecessary(context, TetherUtil.TETHERING_WIFI);
             }