sysinfo: async'ify

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

src/sysinfo/interface.js

@@ -14,16 +14,14 @@ exports = module.exports = {
 var assert = require('assert'),
     BoxError = require('../boxerror.js');
 
-function getServerIp(config, callback) {
+async function getServerIp(config) {
     assert.strictEqual(typeof config, 'object');
-    assert.strictEqual(typeof callback, 'function');
 
-    callback(new BoxError(BoxError.NOT_IMPLEMENTED, 'testConfig is not implemented'));
+    throw new BoxError(BoxError.NOT_IMPLEMENTED, 'testConfig is not implemented');
 }
 
-function testConfig(config, callback) {
+async function testConfig(config) {
     assert.strictEqual(typeof config, 'object');
-    assert.strictEqual(typeof callback, 'function');
 
-    callback(null);
+    return null;
 }