The TCA definition of backend_layout defines "thumbnail=resources"
however the resources field does not exist at all in TYPO3.

The definition should be removed.

Resolves: #77353
Releases: master, 7.6
Change-Id: I76e82becfde1fbefbffc3d3b0d65b05bdc1a52cb
Reviewed-on: https://review.typo3.org/49313


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>