Binary package “userv” in ubuntu xenial

`user services' - program call across trust boundaries

 userv allows one program to invoke another when only limited trust
 exists between them. It is a tool which can be used to avoid having
 to give other system services root privilege, and which allows users
 to more securely have programs provide services to others.
 .
 userv can be useful as `glue' for system administrators; there are
 not many full-blown userv-using applications yet.