[TASK] Replace icon by IconFactory: actions-reference-file

As the icon was missing even before this patch and the function is
only be called in the case of an import from TYPO3 4.5 I took the
liberty to just replace it with the reference-hard icon, to which
it is connected.

Releases: master
Resolves: #68973
Change-Id: I8144379444492aab28c5ae7ec19408c26bb949a3
Reviewed-on: http://review.typo3.org/43234


Reviewed-by: Nicole Cordes <typo3@cordes.co>
Tested-by: Nicole Cordes <typo3@cordes.co>
Reviewed-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Tested-by: Morton Jonuschat <m.jonuschat@mojocode.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>