Merge pull request #8607 from owncloud/filescan_app_hook

Allow apps to control via a hook skipping add/remove a file during filescan

diff --cc config/config.sample.php
Simple merge

diff --cc lib/private/files/cache/scanner.php
index 61b22ea75a0b072f9a64ed919ed6922a946e369d,6dceaf13ec31f24c501923a984addae8364dee02..b97070fcdf0b910e514cffba8192b2b41e6a7cb7
--- 1/lib/private/files/cache/scanner.php
--- 2/lib/private/files/cache/scanner.php
+++ b/lib/private/files/cache/scanner.php
@@@ -41,8 -42,13 +42,13 @@@ class Scanner extends BasicEmitter 
        /**
         * @var \OC\Files\Cache\Permissions $permissionsCache
         */
 -      private $permissionsCache;
 +      protected $permissionsCache;
  
+       /**
+        * @var boolean $cacheActive If true, perform cache operations, if false, do not affect cache
+        */
+       protected $cacheActive;
+ 
        const SCAN_RECURSIVE = true;
        const SCAN_SHALLOW = false;