Update vendor directory

Re-added cobra patch 499475bb41

vendor/golang.org/x/net/trace/events.go

@@ -21,11 +21,6 @@ import (
 	"time"
 )
 
-var eventsTmpl = template.Must(template.New("events").Funcs(template.FuncMap{
-	"elapsed":   elapsed,
-	"trimSpace": strings.TrimSpace,
-}).Parse(eventsHTML))
-
 const maxEventsPerLog = 100
 
 type bucket struct {
@@ -101,7 +96,7 @@ func RenderEvents(w http.ResponseWriter, req *http.Request, sensitive bool) {
 
 	famMu.RLock()
 	defer famMu.RUnlock()
-	if err := eventsTmpl.Execute(w, data); err != nil {
+	if err := eventsTmpl().Execute(w, data); err != nil {
 		log.Printf("net/trace: Failed executing template: %v", err)
 	}
 }
@@ -421,6 +416,19 @@ func freeEventLog(el *eventLog) {
 	}
 }
 
+var eventsTmplCache *template.Template
+var eventsTmplOnce sync.Once
+
+func eventsTmpl() *template.Template {
+	eventsTmplOnce.Do(func() {
+		eventsTmplCache = template.Must(template.New("events").Funcs(template.FuncMap{
+			"elapsed":   elapsed,
+			"trimSpace": strings.TrimSpace,
+		}).Parse(eventsHTML))
+	})
+	return eventsTmplCache
+}
+
 const eventsHTML = `
 <html>
 	<head>