bus-driverd: Fix return code in driver_request_name

RequestName return codes should be consistent with Dbus Specification.

VALUE - DESCRIPTION
1-The caller is now the primary owner of the name, replacing any previous owner,
2-The name already had an owner (QUEUE flag was not specified),
3-The name already has an owner (QUEUE flag was specified),
4-Application trying to request ownership of a name is already the owner of it.
bus: properly return an error code when release_name fails abnormally