title: SCAN_RESULTS_AVAILABLE_ACTION return empty list in Android 6.0
body: <p>Yesterday my Nexus 5 receive the update from <code>Android MNC</code> to version <code>6.0 - Marshmallow</code>.
  Since then, the action to scan the networks available in the device stop receiving the list, in this case the result list have a size of 0, even with 10+ Wifi networks listed in the Wifi system settings.</p>
  
  <p>The code for this is the usual: Register the <code>SCAN_RESULTS_AVAILABLE_ACTION</code> and wait for the event in the Receiver, like this:</p>
  
  <pre><code>// Register the Receiver in some part os fragment...
  getActivity().registerReceiver(wifiListener, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
  WifiManager wifiManager = (WifiManager) getActivity().getSystemService(Context.WIFI_SERVICE);
  wifiManager.startScan();
  
  // Inside the receiver:
  WifiManager wifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
  List&lt;ScanResult&gt; results = wifiManager.getScanResults();
  // the result.size() is 0 after update to Android v6.0, same code working in older devices.
  </code></pre>
  
  <p>I searched in the <a href="http://developer.android.com/preview/behavior-changes.html" rel="noreferrer">changes of the API</a> topic about this, but I didn' see any breaking changes for this functionality. </p>
  
  <p>Did anyone notice this? Is something new in the API or just a isolated case?</p>