Use 'filesystem_check_enable' as a config option.

config/config.sample.php

@@ -291,6 +291,9 @@ $CONFIG = array(
  * 1 -> check each file or folder at most once per request, recomended for general use if outside changes might happen
  * 2 -> check every time the filesystem is used, causes a performance hit when using external storages, not recomended for regular use
  */
-'filesystem_check_changes' => 1
+'filesystem_check_changes' => 1,
+
+/* specifies whether changes in the filesystem outside of owncloud affect cached data about those files */
+'filesystem_check_enable' => 1,
 
 );

lib/private/files/cache/scanner.php

@@ -157,7 +157,7 @@ class Scanner extends BasicEmitter {
 					}
 				}
 				if (!empty($newData)) {
-					$addToCache = Config::getSystemValue('allow_scanner_to_affect_cache', true);
+					$addToCache = Config::getSystemValue('filesystem_check_enable', true);
 					\OC_Hook::emit('Scanner', 'addToCache', array('file' => $file, 'addToCache' => &$addToCache, 'data' => &$newData));
 					if($addToCache) {
 						$data['fileid'] = $this->cache->put($file, $newData);
@@ -166,7 +166,7 @@ class Scanner extends BasicEmitter {
 					\OC_Hook::emit('\OC\Files\Cache\Scanner', 'post_scan_file', array('path' => $file, 'storage' => $this->storageId));
 				}
 			} else {
-				$removeFromCache = Config::getSystemValue('allow_scanner_to_affect_cache', true);
+				$removeFromCache = Config::getSystemValue('filesystem_check_enable', true);
 				\OC_Hook::emit('Scanner', 'removeFromCache', array('file' => $file, 'removeFromCache' => &$removeFromCache));
 				if($removeFromCache) {
 					$this->cache->remove($file);
@@ -253,7 +253,7 @@ class Scanner extends BasicEmitter {
 			$removedChildren = \array_diff($existingChildren, $newChildren);
 			foreach ($removedChildren as $childName) {
 				$child = ($path) ? $path . '/' . $childName : $childName;
-				$removeFromCache = Config::getSystemValue('allow_scanner_to_affect_cache', true);
+				$removeFromCache = Config::getSystemValue('filesystem_check_enable', true);
 				\OC_Hook::emit('Scanner', 'removeFromCache', array('file' => $child, 'removeFromCache' => &$removeFromCache));
 				if($removeFromCache) {
 					$this->cache->remove($child);
@@ -277,7 +277,7 @@ class Scanner extends BasicEmitter {
 				}
 			}
 			$newData = array('size' => $size);
-			$addToCache = Config::getSystemValue('allow_scanner_to_affect_cache', true);
+			$addToCache = Config::getSystemValue('filesystem_check_enable', true);
 			\OC_Hook::emit('Scanner', 'addToCache', array('file' => $child, 'addToCache' => &$addToCache, 'data' => &$newData));
 			if($addToCache) {
 				$this->cache->put($path, $newData);