install (setup.py): don't use sys.prefix for locales

setup.py

@@ -20,7 +20,6 @@
 
 from setuptools import setup, find_packages
 import os
-import sys
 
 NAME = 'sat'
 
@@ -92,7 +91,7 @@ setup(name=NAME,
                    'Operating System :: POSIX :: Linux',
                    'Topic :: Communications :: Chat'],
       packages=find_packages() + ['twisted.plugins'],
-      data_files=[(os.path.join(sys.prefix, 'share/locale/fr/LC_MESSAGES'),
+      data_files=[('share/locale/fr/LC_MESSAGES',
                    ['i18n/fr/LC_MESSAGES/sat.mo']),
                   (os.path.join('share/doc', NAME),
                    ['CHANGELOG', 'COPYING', 'INSTALL', 'README', 'README4TRANSLATORS']),