Update WSL backend to be compat with FCOS defaults

container/common Config was recently updated to use FCOS
default names, since Windows HyperV backend needs them,
and these are common with other providers.

Map this to values the WSL backend expects.

[NO NEW TESTS NEEDED]

Signed-off-by: Jason T. Greene <jason.greene@redhat.com>

pkg/machine/fcos.go

@@ -331,3 +331,18 @@ func FCOSStreamFromString(s string) FCOSStream {
 	}
 	return Stable
 }
+
+func IsValidFCOSStreamString(s string) bool {
+	switch s {
+	case Testing.String():
+		fallthrough
+	case Next.String():
+		fallthrough
+	case PodmanTesting.String():
+		fallthrough
+	case Stable.String():
+		return true
+	}
+
+	return false
+}

pkg/machine/wsl/config.go

@@ -38,8 +38,13 @@ func (p *WSLVirtualization) NewMachine(opts machine.InitOptions) (machine.VM, er
 	vm.ConfigPath = configPath
 	vm.ImagePath = opts.ImagePath
 
-	// WSL uses a different username; here we hardcode it.
-	vm.RemoteUsername = "user"
+	// WSL historically uses a different username; translate "core" fcos default to
+	// legacy "user" default
+	if opts.Username == "" || opts.Username == "core" {
+		vm.RemoteUsername = "user"
+	} else {
+		vm.RemoteUsername = opts.Username
+	}
 
 	vm.Created = time.Now()
 	vm.LastUp = vm.Created

pkg/machine/wsl/machine.go

@@ -388,7 +388,8 @@ func downloadDistro(v *MachineVM, opts machine.InitOptions) error {
 		err error
 	)
 
-	if _, e := strconv.Atoi(opts.ImagePath); e == nil {
+	// The default FCOS stream names are reserved indicators for the standard Fedora fetch
+	if machine.IsValidFCOSStreamString(opts.ImagePath) {
 		v.ImageStream = opts.ImagePath
 		dd, err = NewFedoraDownloader(vmtype, v.Name, opts.ImagePath)
 	} else {