Update vendor dir for kube 1.9 rebase.

vendor/github.com/go-openapi/spec/header.go

@@ -16,7 +16,9 @@ package spec
 
 import (
 	"encoding/json"
+	"strings"
 
+	"github.com/go-openapi/jsonpointer"
 	"github.com/go-openapi/swag"
 )
 
@@ -30,6 +32,7 @@ type HeaderProps struct {
 type Header struct {
 	CommonValidations
 	SimpleSchema
+	VendorExtensible
 	HeaderProps
 }
 
@@ -158,8 +161,35 @@ func (h *Header) UnmarshalJSON(data []byte) error {
 	if err := json.Unmarshal(data, &h.SimpleSchema); err != nil {
 		return err
 	}
+	if err := json.Unmarshal(data, &h.VendorExtensible); err != nil {
+		return err
+	}
 	if err := json.Unmarshal(data, &h.HeaderProps); err != nil {
 		return err
 	}
 	return nil
 }
+
+// JSONLookup look up a value by the json property name
+func (p Header) JSONLookup(token string) (interface{}, error) {
+	if ex, ok := p.Extensions[token]; ok {
+		return &ex, nil
+	}
+
+	r, _, err := jsonpointer.GetForToken(p.CommonValidations, token)
+	if err != nil && !strings.HasPrefix(err.Error(), "object has no field") {
+		return nil, err
+	}
+	if r != nil {
+		return r, nil
+	}
+	r, _, err = jsonpointer.GetForToken(p.SimpleSchema, token)
+	if err != nil && !strings.HasPrefix(err.Error(), "object has no field") {
+		return nil, err
+	}
+	if r != nil {
+		return r, nil
+	}
+	r, _, err = jsonpointer.GetForToken(p.HeaderProps, token)
+	return r, err
+}