Fix etcd egress dialer addr parsing

Kubernetes-commit: a26c392de176494f2c425f712bc49fc399e9ce6d

pkg/storage/storagebackend/factory/etcd3.go

@@ -22,6 +22,7 @@ import (
 	"net"
 	"net/url"
 	"path"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -137,11 +138,15 @@ func newETCD3Client(c storagebackend.TransportConfig) (*clientv3.Client, error)
 	}
 	if egressDialer != nil {
 		dialer := func(ctx context.Context, addr string) (net.Conn, error) {
-			u, err := url.Parse(addr)
-			if err != nil {
-				return nil, err
+			if strings.Contains(addr, "//") {
+				// etcd client prior to 3.5 passed URLs to dialer, normalize to address
+				u, err := url.Parse(addr)
+				if err != nil {
+					return nil, err
+				}
+				addr = u.Host
 			}
-			return egressDialer(ctx, "tcp", u.Host)
+			return egressDialer(ctx, "tcp", addr)
 		}
 		dialOptions = append(dialOptions, grpc.WithContextDialer(dialer))
 	}