migrated multi host connection pool from godropbox package

removing unneeded dependencies, which involved etcd versions.

weed/wdclient/net2/port.go

@@ -0,0 +1,19 @@
+package net2
+
+import (
+	"net"
+	"strconv"
+)
+
+// Returns the port information.
+func GetPort(addr net.Addr) (int, error) {
+	_, lport, err := net.SplitHostPort(addr.String())
+	if err != nil {
+		return -1, err
+	}
+	lportInt, err := strconv.Atoi(lport)
+	if err != nil {
+		return -1, err
+	}
+	return lportInt, nil
+}