fix doc example

README.md

@@ -28,7 +28,7 @@ You can use `goinstall -u -a` for update all installed packages.
     )
 
     func main() {
-         mc := memcache.New("10.0.0.1:11211", "10.0.0.2:11211". "10.0.0.3:11212")
+         mc := memcache.New("10.0.0.1:11211", "10.0.0.2:11211", "10.0.0.3:11212")
          mc.Set(&memcache.Item{Key: "foo", Value: []byte("my value")})
 
          it, err := mc.Get("foo")