[BUGFIX] Use title property for File Links

Instead of the alternative text the title of files need to be
used for titles of File Links.

Resolves: #66347
Releases: master, 6.2
Change-Id: I8470b92017527ad87a9d53eb1541a2b491eacba8
Reviewed-on: http://review.typo3.org/38611


Reviewed-by: Andreas Fernandez <andreas.fernandez@aspedia.de>
Tested-by: Andreas Fernandez <andreas.fernandez@aspedia.de>
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>