Make warning about failing IPV6_V6ONLY info level.

We might have a bug where bindtoaddr() tries to set V6ONLY on IPv4
sockets. Until that's been resolved, don't alarm users on debug level
'warning'.

util.c

@@ -155,7 +155,7 @@ int bindtoaddr(struct addrinfo *addrinfo, int family, int reuse, int v6only) {
 #ifdef IPV6_V6ONLY
 	if (v6only)
 	    if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) == -1)
-                debugerrno(errno, DBG_WARN, "Failed to set IPV6_V6ONLY");
+                debugerrno(errno, DBG_INFO, "Failed to set IPV6_V6ONLY");
 #endif
 	if (!bind(s, res->ai_addr, res->ai_addrlen))
 	    return s;