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 .
delAction is not good because it's not an object only for deletion.
And the next method deleteNoOnwerActionList() is also unreadable, because
the target of the deletion is not a list, but actions themselves.

I suggest the following names.
  dbAction->deleteNoOwnerActions();