remove detecting ipv6

Got this error on my local:

transport: Error while dialing dial tcp [fe80::1]:19333: connect: no route to host

related to https://github.com/chrislusf/seaweedfs/pull/2310

weed/util/network.go

@@ -24,7 +24,7 @@ func DetectedHostAddress() string {
 
 		for _, a := range addrs {
 			if ipNet, ok := a.(*net.IPNet); ok && !ipNet.IP.IsLoopback() {
-				if ipNet.IP.To4() != nil || ipNet.IP.To16() != nil {
+				if ipNet.IP.To4() != nil {
 					return ipNet.IP.String()
 				}
 			}