Work around deprecation of platform.dist() in recent python

setup.py

@@ -95,11 +95,14 @@ if __name__ == "__main__":
             ['desktop/icons/24x24/pybitmessage.png'])
     ]
 
+    try:
         if platform.dist()[0] in ('Debian', 'Ubuntu'):
             data_files += [
                 ("etc/apparmor.d/",
                     ['packages/apparmor/pybitmessage'])
             ]
+    except AttributeError:
+        pass  # FIXME: use distro for more recent python
 
     dist = setup(
         name='pybitmessage',