Fix pyrax version.
Fix pyrax version.

jean/pybossa,stefanhahmann/pybossa,OpenNewsLabs/pybossa,jean/pybossa,geotagx/pybossa,PyBossa/pybossa,harihpr/tweetclickers,inteligencia-coletiva-lsd/pybossa,stefanhahmann/pybossa,geotagx/pybossa,Scifabric/pybossa,inteligencia-coletiva-lsd/pybossa,harihpr/tweetclickers,Scifabric/pybossa,PyBossa/pybossa,OpenNewsLabs/pybossa