Add LCOW behind experimental,

might not be the cleanest way, but it's definitly the way with the
minimum code change.

Signed-off-by: Victor Vieux <victorvieux@gmail.com>
Upstream-commit: ff686743c50dc34b57f5627ba6fee38502bdd3ec
Component: engine

components/engine/cmd/dockerd/daemon.go

@@ -99,6 +99,8 @@ func (cli *DaemonCli) start(opts *daemonOptions) (err error) {
 		FullTimestamp:   true,
 	})
 
+	system.InitLCOW(cli.Config.Experimental)
+
 	if err := setDefaultUmask(); err != nil {
 		return fmt.Errorf("Failed to set umask: %v", err)
 	}

components/engine/pkg/system/init_unix.go

@@ -0,0 +1,7 @@
+// +build !windows
+
+package system
+
+// InitLCOW does nothing since LCOW is a windows only feature
+func InitLCOW(experimental bool) {
+}

components/engine/pkg/system/init_windows.go

@@ -8,9 +8,10 @@ import "os"
 // on build number. @jhowardmsft
 var lcowSupported = false
 
-func init() {
+// InitLCOW sets whether LCOW is supported or not
+func InitLCOW(experimental bool) {
 	// LCOW initialization
-	if os.Getenv("LCOW_SUPPORTED") != "" {
+	if experimental && os.Getenv("LCOW_SUPPORTED") != "" {
 		lcowSupported = true
 	}