certs: fix renewal notification

src/mailer.js

@@ -228,22 +228,23 @@ function backupFailed(mailTo, errorMessage, logUrl) {
     });
 }
 
-function certificateRenewalError(mailTo, domain, message) {
+function certificateRenewalError(mailTo, domain, message, callback) {
     assert.strictEqual(typeof mailTo, 'string');
     assert.strictEqual(typeof domain, 'string');
     assert.strictEqual(typeof message, 'string');
+    assert.strictEqual(typeof callback, 'function');
 
     getMailConfig(function (error, mailConfig) {
         if (error) return debug('Error getting mail details:', error);
 
-        var mailOptions = {
+        const mailOptions = {
             from: mailConfig.notificationFrom,
             to: mailTo,
             subject: `[${mailConfig.cloudronName}] Certificate renewal error`,
             text: render('certificate_renewal_error.ejs', { domain: domain, message: message, format: 'text' })
         };
 
-        sendMail(mailOptions);
+        sendMail(mailOptions, callback);
     });
 }