Do not send out emails for out of disk

We rely now on notifications. We should hover send emails about critical
new notifications. Lets make the admin go to the dashboard to check the
situation.

src/mailer.js

@@ -15,7 +15,6 @@ exports = module.exports = {
     appDied: appDied,
     oomEvent: oomEvent,
 
-    outOfDiskSpace: outOfDiskSpace,
     backupFailed: backupFailed,
 
     certificateRenewalError: certificateRenewalError,
@@ -32,7 +31,6 @@ var assert = require('assert'),
     debug = require('debug')('box:mailer'),
     docker = require('./docker.js').connection,
     ejs = require('ejs'),
-    mail = require('./mail.js'),
     nodemailer = require('nodemailer'),
     path = require('path'),
     safe = require('safetydance'),
@@ -440,24 +438,6 @@ function sendDigest(info) {
     });
 }
 
-function outOfDiskSpace(mailTo, message) {
-    assert.strictEqual(typeof mailTo, 'string');
-    assert.strictEqual(typeof message, 'string');
-
-    getMailConfig(function (error, mailConfig) {
-        if (error) return debug('Error getting mail details:', error);
-
-        var mailOptions = {
-            from: mailConfig.notificationFrom,
-            to: mailTo,
-            subject: util.format('[%s] Out of disk space alert', mailConfig.cloudronName),
-            text: render('out_of_disk_space.ejs', { cloudronName: mailConfig.cloudronName, message: message, format: 'text' })
-        };
-
-        sendMails([ mailOptions ]);
-    });
-}
-
 function backupFailed(error) {
     var message = splatchError(error);