Fix 'super' object has no attribute 'getpeername' error while using gevent

[jophy]

when I import the monkey patch of gevent , it shows an error:

AttributeError: 'super' object has no attribute 'getpeername'

File "socks.py", line 480, in get_proxy_peername
return super(socksocket, self).getpeername()

I try to figure out, that return self.getpeername() just fine.

So I make a PR here.

Also there is a discussion in gevent repo.
gevent/gevent#937

[jophy]

#88 HERE