issue #107, Remove the Action of without owner.

When remove the "User", to remove the "access_list" together, but don't remove "actions". 
When displaying the "actions", to display only the "actions" that the user(owner) is exists. 
To delete the "actions", run the deletion process on a cyclic(example:3600sec(1h)), 
to remove an "actions" if there is no owner user.However, USER_ID_SYSTEM is excluded .
I also prefer to include the unit to the variable name. Because we can know about the unit wherever the variable name is used. If we put the unit to only the definition line as a comment, we can know about the unit only the definition line.