Fix a non-ASCII character.

A wrong char prevents inet6 from being loaded (and thus, a lot of modules):
WARNING: can't import layer inet: Non-ASCII character '\xc2' in file scapy/layers/inet6.py on line 341, but no encoding declared; see http://www.python.org/peps/pep-0263.html for details (inet6.py, line 341)
...

--HG--
branch : space fix