Fix : admin user can't clear their own session but can clear other user sessions [SDESK-6696]. (#2398)
Fix : admin user can't clear their own session but can clear other user sessions [SDESK-6696]. (#2398)

* admin user can't clear their own session but can clear other user sessions [SDESK-6696]

* Delete all session except current session

* Refactoring the code
superdesk/superdesk-core,superdesk/superdesk-core,superdesk/superdesk-core,superdesk/superdesk-core