Fix Python package meta_data license

Author: fboender

setup.py

@@ -61,7 +61,7 @@ def get_data_files(path, strip='', prefix=''):
         'Intended Audience :: Developers',
         'Intended Audience :: Information Technology',
         'Intended Audience :: System Administrators',
-        'License :: OSI Approved :: BSD License',
+        'License :: OSI Approved :: GNU General Public License v3 (GPLv3)',
         'Natural Language :: English',
         'Operating System :: POSIX',
         'Programming Language :: Python',