httpproxy: init the rand that we use to randomize endpoints

This is actually does not change anything. The endpoints are already
randomized before feeding into proxy. But it makes the proxy more safe.

proxy/httpproxy/director.go

@@ -27,6 +27,10 @@ const defaultRefreshInterval = 30000 * time.Millisecond
 
 var once sync.Once
 
+func init() {
+	rand.Seed(time.Now().UnixNano())
+}
+
 func newDirector(urlsFunc GetProxyURLs, failureWait time.Duration, refreshInterval time.Duration) *director {
 	d := &director{
 		uf:          urlsFunc,