minor #18990 [FrameworkBundle] Remove unused variable (dunglas)

This PR was merged into the 3.1 branch.

Discussion
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[FrameworkBundle] Remove unused variable

| Q             | A
| ------------- | ---
| Branch?       |3.1
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

Commits
-------

f6229c7 [FrameworkBundle] Remove unused variable

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

@@ -126,7 +126,7 @@ public function load(array $configs, ContainerBuilder $container)
         $this->registerFragmentsConfiguration($config['fragments'], $container, $loader);
         $this->registerTranslatorConfiguration($config['translator'], $container);
         $this->registerProfilerConfiguration($config['profiler'], $container, $loader);
-        $this->registerCacheConfiguration($config['cache'], $container, $loader);
+        $this->registerCacheConfiguration($config['cache'], $container);
 
         if ($this->isConfigEnabled($container, $config['router'])) {
             $this->registerRouterConfiguration($config['router'], $container, $loader);
@@ -1035,7 +1035,7 @@ private function registerPropertyInfoConfiguration(array $config, ContainerBuild
         }
     }
 
-    private function registerCacheConfiguration(array $config, ContainerBuilder $container, XmlFileLoader $loader)
+    private function registerCacheConfiguration(array $config, ContainerBuilder $container)
     {
         $version = substr(str_replace('/', '-', base64_encode(md5(uniqid(mt_rand(), true), true))), 0, -2);
         $container->getDefinition('cache.adapter.apcu')->replaceArgument(2, $version);