Network: Do not default to Wi-Fi icons in the Interfaces preflet.

At least TUN/TAP don't appear with the "wireless" icon anymore.

src/preferences/network/InterfaceListItem.cpp

@@ -172,7 +172,6 @@ void
 InterfaceListItem::_Init()
 {
 	switch (fType) {
-		default:
 		case B_NETWORK_INTERFACE_TYPE_WIFI:
 			_PopulateBitmaps("wifi");
 			break;
@@ -185,6 +184,9 @@ InterfaceListItem::_Init()
 		case B_NETWORK_INTERFACE_TYPE_DIAL_UP:
 			_PopulateBitmaps("dialup");
 			break;
+		default:
+			_PopulateBitmaps(NULL);
+			break;
 	}
 }