[TASK] Remove media folder icon

It makes no sense to keep the media folder icon
since records form sys_file have a mandatory pid = 0

Change-Id: I770297e9a93fe5098bc71fa81cee751a266b1d95
Release: 3.0
Resolves: #61348
Reviewed-on: http://review.typo3.org/32581
Reviewed-by: Fabien Udriot <fabien.udriot@ecodev.ch>
Tested-by: Fabien Udriot <fabien.udriot@ecodev.ch>