Replace UTF-8 symbol in comment with its ASCII equivalent

Fixes:

```
SyntaxError: Non-ASCII character '\xe2' in file .../.env/src/atomac/atomac/ldtpd/utils.py on line 334, but no encoding declared; see http://www.python.org/peps/pep-0263.html for details
```

Happens when you use latest pyatom from sources. Happens on Mac OS 10.9.3 with Python 2.7.5