vendor: update dependencies to latest

vendor/google.golang.org/appengine/internal/api.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 // +build !appengine
-// +build go1.7
 
 package internal
 
@@ -130,7 +129,13 @@ func handleHTTP(w http.ResponseWriter, r *http.Request) {
 		flushes++
 	}
 	c.pendingLogs.Unlock()
-	go c.flushLog(false)
+	flushed := make(chan struct{})
+	go func() {
+		defer close(flushed)
+		// Force a log flush, because with very short requests we
+		// may not ever flush logs.
+		c.flushLog(true)
+	}()
 	w.Header().Set(logFlushHeader, strconv.Itoa(flushes))
 
 	// Avoid nil Write call if c.Write is never called.
@@ -140,6 +145,9 @@ func handleHTTP(w http.ResponseWriter, r *http.Request) {
 	if c.outBody != nil {
 		w.Write(c.outBody)
 	}
+	// Wait for the last flush to complete before returning,
+	// otherwise the security ticket will not be valid.
+	<-flushed
 }
 
 func executeRequestSafely(c *context, r *http.Request) {