Merge pull request #22974 from owncloud/php-automagics-type-conversion-is-fun

Use "hasKey" instead of checking the value

apps/files_sharing/lib/external/storage.php

@@ -253,8 +253,8 @@ class Storage extends DAV implements ISharedStorage {
 	 */
 	private function testRemoteUrl($url) {
 		$cache = $this->memcacheFactory->create('files_sharing_remote_url');
-		if($result = $cache->get($url)) {
-			return (bool)$result;
+		if($cache->hasKey($url)) {
+			return (bool)$cache->get($url);
 		}
 
 		$result = file_get_contents($url);