Fix a test that wasn't mocking enough (#590)

The implementation of the ManagerRegistry resetService started
using another method of the Container interface that wasn't mocked
and it broke the tests. The initialized method.
This PR just mock that method in the relevant tests.

Tests/RegistryTest.php

@@ -119,6 +119,10 @@ public function testGetUnknownEntityManager()
     public function testResetDefaultEntityManager()
     {
         $container = $this->getMock('Symfony\Component\DependencyInjection\ContainerInterface');
+        $container->expects($this->any())
+            ->method('initialized')
+            ->with($this->equalTo('doctrine.orm.default_entity_manager'))
+            ->willReturn(true);
         $container->expects($this->once())
                   ->method('set')
                   ->with($this->equalTo('doctrine.orm.default_entity_manager'), $this->equalTo(null));
@@ -130,6 +134,10 @@ public function testResetDefaultEntityManager()
     public function testResetEntityManager()
     {
         $container = $this->getMock('Symfony\Component\DependencyInjection\ContainerInterface');
+        $container->expects($this->any())
+            ->method('initialized')
+            ->with($this->equalTo('doctrine.orm.default_entity_manager'))
+            ->willReturn(true);
         $container->expects($this->once())
                   ->method('set')
                   ->with($this->equalTo('doctrine.orm.default_entity_manager'), $this->equalTo(null));