Fix IPv4 operations where v6only behavior is default

Some configurations disable dual stack sockets.  For example
if net.ipv6.bindv6only is 1 in linux, pyghmi was failing.
Address by explicitly requesting the converse behavior
on the socket since we explicitly do want to not care
whether a particular socket is engaged in ipv4 or ipv6
activity.

Change-Id: I17a16f0ebe4752ca743f115af39a367670691507

pyghmi/ipmi/private/session.py

@@ -287,6 +287,7 @@ class Session(object):
         tmpsocket = _io_apply(socket.socket,
                               (socket.AF_INET6, socket.SOCK_DGRAM))  # INET6
                                     # can do IPv4 if you are nice to it
+        tmpsocket.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, 0)
         self.socketpool[tmpsocket] = 1
         iosockets.append(tmpsocket)
         return tmpsocket