[BUGFIX] Warning in list module

The function addElement needs to have an array as third argument.

Change-Id: Ief786c358476da4d691cb89212b19c397b4a353f
Fixes: #39678
Releases: 4.5, 4.6, 4.7, 6.0
Reviewed-on: http://review.typo3.org/13559
Reviewed-by: Michael Cannon
Reviewed-by: Mattias Nilsson
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel