[TASK] GGL violation "Tabs must be used to indent lines"

Change-Id: Icdf2b997282ff6934ae0fe5563f9a797fcc4b863
Resolves: #41472
Releases: 6.0
Reviewed-on: http://review.typo3.org/15167
Reviewed-by: Philipp Gampe
Reviewed-by: Wouter Wolters
Tested-by: Philipp Gampe
Reviewed-by: Oliver Klee
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn