Revert "Disable docker system dial-stdio on Windows"

This reverts commit c41c23813c.

This case is now handled due to the previous commit.

Signed-off-by: Ian Campbell <ijc@docker.com>

cli-plugins/plugin/plugin.go

@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"os"
-	"runtime"
 	"sync"
 
 	"github.com/docker/cli/cli"
@@ -75,11 +74,7 @@ func PersistentPreRunE(cmd *cobra.Command, args []string) error {
 		}
 		// flags must be the original top-level command flags, not cmd.Flags()
 		options.opts.Common.SetDefaultOptions(options.flags)
-		var initopts []command.InitializeOpt
-		if runtime.GOOS != "windows" {
-			initopts = append(initopts, withPluginClientConn(options.name))
-		}
-		err = options.dockerCli.Initialize(options.opts, initopts...)
+		err = options.dockerCli.Initialize(options.opts, withPluginClientConn(options.name))
 	})
 	return err
 }