Issue #2686595 by sidharthap: LibraryDiscoveryCollector does not need to...

Issue #2686595 by sidharthap: LibraryDiscoveryCollector does not need to override properties of the parent class

core/lib/Drupal/Core/Asset/LibraryDiscoveryCollector.php

@@ -20,20 +20,6 @@
  */
 class LibraryDiscoveryCollector extends CacheCollector {
 
-  /**
-   * The cache backend.
-   *
-   * @var \Drupal\Core\Cache\CacheBackendInterface
-   */
-  protected $cache;
-
-  /**
-   * The lock backend.
-   *
-   * @var \Drupal\Core\Lock\LockBackendInterface
-   */
-  protected $lock;
-
   /**
    * The library discovery parser.
    *