[BUGFIX] Cache FileBackend does not respect fileCreateMask

Change-Id: Ia786457dbc4c850c67f7293be38b2591786f1553
Resolves: #28323
Releases: 4.6
Reviewed-on: http://review.typo3.org/3422
Reviewed-by: Fabrizio Branca
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe
Reviewed-by: Stefan Neufeind
Reviewed-by: Steffen Ritter
Tested-by: Steffen Ritter