Relax validation for configuration without root disk device

If there's no root disk in the config, validation fails while trying to
stat path `""`.

Signed-off-by: Andrey Smirnov <[email protected]>

Author: smira

machine.go

@@ -134,18 +134,17 @@ func (cfg *Config) Validate() error {
 		return fmt.Errorf("failed to stat kernel image path, %q: %v", cfg.KernelImagePath, err)
 	}
 
-	rootPath := ""
 	for _, drive := range cfg.Drives {
 		if BoolValue(drive.IsRootDevice) {
-			rootPath = StringValue(drive.PathOnHost)
+			rootPath := StringValue(drive.PathOnHost)
+			if _, err := os.Stat(rootPath); err != nil {
+				return fmt.Errorf("failed to stat host path, %q: %v", rootPath, err)
+			}
+
 			break
 		}
 	}
 
-	if _, err := os.Stat(rootPath); err != nil {
-		return fmt.Errorf("failed to stat host path, %q: %v", rootPath, err)
-	}
-
 	// Check the non-existence of some files:
 	if _, err := os.Stat(cfg.SocketPath); err == nil {
 		return fmt.Errorf("socket %s already exists", cfg.SocketPath)