Fix renamming first derivation

lib/models/walletOptions.dart

@@ -136,8 +136,6 @@ class WalletOptionsProvider with ChangeNotifier {
 
     String newConfig =
         await _walletConfig.readAsLines().then((List<String> lines) {
-      int nbrLines = lines.length;
-      if (nbrLines != 1) {
       for (String wLine in lines) {
         String wID = "${wLine.split(':')[0]}:${wLine.split(':')[1]}";
         String deri = wLine.split(':')[3];
@@ -147,9 +145,6 @@ class WalletOptionsProvider with ChangeNotifier {
         }
       }
       return lines.join('\n');
-      } else {
-        return 'true';
-      }
     });
 
     await _walletConfig.delete();