notify: Webhook endpoints can fail, but we must start the server. (#4060)

Ignore any network errors when registering a webhook
notifier during Minio startup sequence. This way server
can be started even if the webhook endpoint is not available
and unreachable.

cmd/event-notifier.go

@@ -645,7 +645,6 @@ func loadAllQueueTargets() (map[string]*logrus.Logger, error) {
 		if !webhookN.Enable {
 			continue
 		}
-
 		if _, err := addQueueTarget(queueTargets, accountID, queueTypeWebhook, newWebhookNotify); err != nil {
 			return nil, err
 		}