use api.Config.Timeout instead of http.Client.Timeout for 60s request timeout default (#7469)

api/client.go

@@ -140,8 +140,8 @@ func DefaultConfig() *Config {
 	config := &Config{
 		Address:    "https://127.0.0.1:8200",
 		HttpClient: cleanhttp.DefaultPooledClient(),
+		Timeout:    time.Second * 60,
 	}
-	config.HttpClient.Timeout = time.Second * 60
 
 	transport := config.HttpClient.Transport.(*http.Transport)
 	transport.TLSHandshakeTimeout = 10 * time.Second