* reverted global rename of function _dbus_username_from_current_process.

* reverted global rename of function _dbus_username_from_current_process.
It needs to much tests to verify that the change does not break anything. I had overseen that the signatures are different (** to *) which requires non trivial changes. This is one *major* disadvantage of elumating oop functionality with c. You are responsible for cleaning every object on every function return point, which could be a nightmare if you are not working with dbus all the days.