The classname field has been removed from the scheduler
but has been forgotten to be removed when inserting a task

Remove that last occurrence, too.

Releases: 6.0

Change-Id: I54823d80b9a9a0f0cffdab3d76690b00b5522b19
Reviewed-on: http://review.typo3.org/16082
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel