bug #20957 [FrameworkBundle] test for the Validator component to be p…

…resent (xabbuh)

This PR was merged into the 2.7 branch.

Discussion
----------

[FrameworkBundle] test for the Validator component to be present

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #20949
| License       | MIT
| Doc PR        |

Commits
-------

fb9b083 test for the Validator component to be present

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php

@@ -751,6 +751,10 @@ private function registerValidationConfiguration(array $config, ContainerBuilder
             return;
         }
 
+        if (!class_exists('Symfony\Component\Validator\Validation')) {
+            throw new LogicException('Validation support cannot be enabled as the Validator component is not installed.');
+        }
+
         $loader->load('validator.xml');
 
         $validatorBuilder = $container->getDefinition('validator.builder');