bug symfony#23195 [FrameworkBundle] [Command] Clean bundle directory, fixes symfony#23177 (NicolasPion)

This PR was squashed before being merged into the 2.7 branch (closes symfony#23195).

Discussion
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[FrameworkBundle] [Command] Clean bundle directory, fixes symfony#23177

| Q             | A
| ------------- | ---
| Branch?       | 2.7 <!-- see comment below -->
| Bug fix?      | yes
| New feature?  | no <!-- don't forget updating src/**/CHANGELOG.md files -->
| BC breaks?    | no
| Deprecations? | no <!-- don't forget updating UPGRADE-*.md files -->
| Tests pass?   | no
| Fixed tickets | symfony#23177
| License       | MIT

This PR fix symfony#23177
when running an assets:install, it will remove directorys who do not have anymore a valid Bundle

Commits
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180f178 [FrameworkBundle] [Command] Clean bundle directory, fixes symfony#23177

Author: fabpot

src/Symfony/Bundle/FrameworkBundle/Command/AssetsInstallCommand.php

@@ -89,6 +89,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
             $output->writeln('Installing assets as <comment>hard copies</comment>.');
         }
 
+        $validAssetDirs = array();
         foreach ($this->getContainer()->get('kernel')->getBundles() as $bundle) {
             if (is_dir($originDir = $bundle->getPath().'/Resources/public')) {
                 $targetDir = $bundlesDir.preg_replace('/bundle$/', '', strtolower($bundle->getName()));
@@ -131,6 +132,13 @@ protected function execute(InputInterface $input, OutputInterface $output)
                 } else {
                     $this->hardCopy($originDir, $targetDir);
                 }
+                $validAssetDirs[] = $targetDir;
+            }
+        }
+        // remove the assets of the bundles that no longer exist
+        foreach (new \FilesystemIterator($bundlesDir) as $dir) {
+            if (!in_array($dir, $validAssetDirs)) {
+                $filesystem->remove($dir);
             }
         }
     }