examples: python: print into stderr

https://mail.gnome.org/archives/networkmanager-list/2015-March/msg00024.html

Signed-off-by: Petr Vorel <petr.vorel@gmail.com>

examples/python/gi/add_connection.py

@@ -69,7 +69,7 @@ def added_cb(client, result, data):
         client.add_connection_finish(result)
         print("The connection profile has been succesfully added to NetworkManager.")
     except Exception, e:
-        print("Error: %s" % e)
+        sys.stderr.write("Error: %s\n" % e)
     main_loop.quit()
 
 if __name__ == "__main__":