[BUGFIX] Upload fails if TYPO3 is installed on sub-directory

Change-Id: Ie605573d01ad88b75977c176ec88a6f773b97753
Releases: 2.0.1
Resolves: #54767
Reviewed-on: https://review.typo3.org/26668
Reviewed-by: Fabien Udriot
Tested-by: Fabien Udriot