IP address change detection does not trigger new REGISTER request.

```
What steps will reproduce the problem?
1. If you switch from 3G to Wifi or vice versa there is a change in IP
2. Looking at the code, Only a pop-up toast with sound is generated with no
associated REGISTER to adapt to the new IP
3.

What is the expected output? What do you see instead?

One would expect IMSdroid to function even after the change in IP without
having to exit and restart

What version of the product are you using? On what operating system?

Android version 2.1 on Samsung Galaxy

Please provide any additional information below.

public class ConnectionChangeReceiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
if(ServiceManager.getSipService().isRegistered()){
Toast.makeText(IMSDroid.getContext(), "IMSDroid: Connect
ion information have changed", Toast.LENGTH_LONG).show();
ServiceManager.getSoundService().playNewEvent();
}
}

}
```

Original issue reported on code.google.com by `saket...@gmail.com` on 6 Oct 2010 at 9:47