\TYPO3\CMS\Core\Utility\GeneralUtility::flushDirectory fails if the directory specified is a symlink
This affects cache flushing where this API method is used.
The reason this fails is, that it is tried to rename the directory (which in fact is a symlink) to allow atomic flushing of the directory.
Steps to reproduce:
- make va/cache a symlink to any folder
- execute cache flush in install tool