Kraken: fix error when deleting disruption with multiple impacts
Kraken: fix error when deleting disruption with multiple impacts

When we are deleting an impact on a meta_vj we make sure we are not
reapplying the current disruption we are trying to delete.
If there is other impacts from the same disruption we keep the link in
modified_by to allow a clean deletion.

xlqian/navitia,patochectp/navitia,Tisseo/navitia,patochectp/navitia,CanalTP/navitia,xlqian/navitia,xlqian/navitia,patochectp/navitia,pbougue/navitia,xlqian/navitia,pbougue/navitia,CanalTP/navitia,xlqian/navitia,Tisseo/navitia,kinnou02/navitia,CanalTP/navitia,pbougue/navitia,CanalTP/navitia,kinnou02/navitia,patochectp/navitia,CanalTP/navitia,Tisseo/navitia,pbougue/navitia,kinnou02/navitia,kinnou02/navitia,Tisseo/navitia,Tisseo/navitia