migrate to go modules

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

vendor/github.com/Microsoft/hcsshim/internal/hcserror/hcserror.go

@@ -0,0 +1,47 @@
+package hcserror
+
+import (
+	"fmt"
+	"syscall"
+)
+
+const ERROR_GEN_FAILURE = syscall.Errno(31)
+
+type HcsError struct {
+	title string
+	rest  string
+	Err   error
+}
+
+func (e *HcsError) Error() string {
+	s := e.title
+	if len(s) > 0 && s[len(s)-1] != ' ' {
+		s += " "
+	}
+	s += fmt.Sprintf("failed in Win32: %s (0x%x)", e.Err, Win32FromError(e.Err))
+	if e.rest != "" {
+		if e.rest[0] != ' ' {
+			s += " "
+		}
+		s += e.rest
+	}
+	return s
+}
+
+func New(err error, title, rest string) error {
+	// Pass through DLL errors directly since they do not originate from HCS.
+	if _, ok := err.(*syscall.DLLError); ok {
+		return err
+	}
+	return &HcsError{title, rest, err}
+}
+
+func Win32FromError(err error) uint32 {
+	if herr, ok := err.(*HcsError); ok {
+		return Win32FromError(herr.Err)
+	}
+	if code, ok := err.(syscall.Errno); ok {
+		return uint32(code)
+	}
+	return uint32(ERROR_GEN_FAILURE)
+}