Please describe the problem:
See summary.  Init is called fine, as are link and unlink, but not shutdown.

Steps to reproduce:
1. include sample_datasource plugin
2. install the atl_last function within a cell
3. clear the function from the cell, close the workbook, exit gnumeric


Actual results:
Nothing...

Expected results:
At some point shutdown should be called...

Does this happen every time?
Yup.

Other information:
This is probably a goffice issue, but I am not sure.