[BUGFIX] Random PHP warning unlinking valid cache file

Sometimes, although a valid cache path and filename is given to unlink(),
it generates a PHP warning as if the file did not exist.

Change-Id: I3ff65cafaf22cb925a9ce395aa9d0fb52ee2b529
Resolves: #67802
Releases: master
Reviewed-on: http://review.typo3.org/40713


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>

typo3/sysext/core/Classes/Cache/Backend/FileBackend.php

@@ -237,7 +237,7 @@ class FileBackend extends \TYPO3\CMS\Core\Cache\Backend\SimpleFileBackend implem
 		if (file_exists($pathAndFilename) === FALSE) {
 			return FALSE;
 		}
-		if (unlink($pathAndFilename) === FALSE) {
+		if (@unlink($pathAndFilename) === FALSE) {
 			return FALSE;
 		}
 		return TRUE;