qgis/Quantum-GIS — pull request #781 by slarosa (2013-08-02 19:37:49+00:00)
Title: fix list unique value tool: skip QPyNullVariant

If you use 'List unique values' tool on a layer with some NULL attribute values you'll get:
![qpynullvariant](https://f.cloud.github.com/assets/1374682/903384/13fe5ef0-fbaa-11e2-8ea4-fdd95f4fe86c.png)