qi_create_python_ext: fix for mac and windows

* set correct name on all platforms

Change-Id: I71e0ccab586c9f1ee12e9db9b79ddbe338fa87df
Reviewed-on: http://gerrit.aldebaran.lan/40149
Reviewed-by: dmerejkowsky <dmerejkowsky@aldebaran-robotics.com>
Tested-by: dmerejkowsky <dmerejkowsky@aldebaran-robotics.com>