[BUGFIX] Correct permissions of new files

Set the correct file permissions of files created with
FAL according to the fileCreateMask.

Change-Id: I4d6562f926cd79a98c3d6b0545a14915c1d7a766
Resolves: #49029
Releases: 6.0, 6.1, 6.2
Reviewed-on: https://review.typo3.org/21532
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn