kf5: port away from kWarning

use qCWarning() instead
also remove KDEBUG_BLOCK

Signed-off-by: Laurent Navet <laurent.navet@gmail.com>
add missing <KSharedPtr> include

KSharedPtr should be next ported to QExplicitlySharedDataPointer

Signed-off-by: Laurent Navet <laurent.navet@gmail.com>