sysinfo: async'ify

in the process, provision, dyndns, mail, dns also got further asyncified

src/sysinfo/fixed.js

@@ -5,23 +5,21 @@ exports = module.exports = {
     testConfig
 };
 
-var assert = require('assert'),
+const assert = require('assert'),
     BoxError = require('../boxerror.js'),
     validator = require('validator');
 
-function getServerIp(config, callback) {
+async function getServerIp(config) {
     assert.strictEqual(typeof config, 'object');
-    assert.strictEqual(typeof callback, 'function');
 
-    callback(null, config.ip);
+    return config.ip;
 }
 
-function testConfig(config, callback) {
+async function testConfig(config) {
     assert.strictEqual(typeof config, 'object');
-    assert.strictEqual(typeof callback, 'function');
 
-    if (typeof config.ip !== 'string') return callback(new BoxError(BoxError.BAD_FIELD, 'ip must be a string'));
-    if (!validator.isIP(config.ip, 4)) return callback(new BoxError(BoxError.BAD_FIELD, 'ip is not a valid ipv4'));
+    if (typeof config.ip !== 'string') return new BoxError(BoxError.BAD_FIELD, 'ip must be a string');
+    if (!validator.isIP(config.ip, 4)) return new BoxError(BoxError.BAD_FIELD, 'ip is not a valid ipv4');
 
-    callback(null);
+    return null;
 }