polkit: Remove authentication override as it is handled in OE-Core

OE-Core now handles the detection of authentication so we don't need
to do it here. The bbappend file is kept to provide the upgrade path
only, or the revision would go backwards.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>