aarifullin/frostfs-node:fix/574-cnt_ever_existed
master
Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>
* Introduce common method EverExisted * Define DeletionInfo for struct that must implement Source * Refactor tree srv Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>