create toggleDefault method in lang method and modify in Country model

core/lib/Thelia/Model/Country.php

@@ -3,9 +3,12 @@
 namespace Thelia\Model;
 
 use Propel\Runtime\Connection\ConnectionInterface;
+use Propel\Runtime\Exception\PropelException;
+use Propel\Runtime\Propel;
 use Thelia\Core\Event\Country\CountryEvent;
 use Thelia\Core\Event\TheliaEvents;
 use Thelia\Model\Base\Country as BaseCountry;
+use Thelia\Model\Map\CountryTableMap;
 
 class Country extends BaseCountry
 {
@@ -16,13 +19,25 @@ class Country extends BaseCountry
         if($this->getId() === null) {
             throw new \RuntimeException("impossible to just uncheck default country, choose a new one");
         }
-        CountryQuery::create()
-            ->filterByByDefault(1)
-            ->update(array('ByDefault' => 0));
 
-        $this
-            ->setByDefault(1)
-            ->save();
+        $con = Propel::getWriteConnection(CountryTableMap::DATABASE_NAME);
+        $con->beginTransaction();
+
+        try {
+            CountryQuery::create()
+                ->filterByByDefault(1)
+                ->update(array('ByDefault' => 0), $con);
+
+            $this
+                ->setByDefault(1)
+                ->save($con);
+
+            $con->commit();
+        } catch(PropelException $e) {
+            $con->rollBack();
+            throw $e;
+        }
+
     }
 
     public function preInsert(ConnectionInterface $con = null)