Do not restart tethering while enabling tethering.

Change-Id: I64194cfbcf830d867593681ab960fea0213ef24a
Fixes: 110303540
Test: manual

packages/SystemUI/src/com/android/systemui/statusbar/policy/HotspotControllerImpl.java

@@ -134,6 +134,10 @@ public class HotspotControllerImpl implements HotspotController, WifiManager.Sof
 
     @Override
     public void setHotspotEnabled(boolean enabled) {
+        if (mWaitingForCallback) {
+            if (DEBUG) Log.d(TAG, "Ignoring setHotspotEnabled; waiting for callback.");
+            return;
+        }
         if (enabled) {
             OnStartTetheringCallback callback = new OnStartTetheringCallback();
             mWaitingForCallback = true;