removed references to libs that aren't used

src/messaging/notifications.js

@@ -1,7 +1,6 @@
 'use strict';
 
 var async = require('async');
-var nconf = require('nconf');
 var winston = require('winston');
 
 var user = require('../user');

src/socket.io/admin.js

@@ -2,7 +2,6 @@
 
 var async = require('async');
 var winston = require('winston');
-var nconf = require('nconf');
 
 var meta = require('../meta');
 var plugins = require('../plugins');

src/topics/follow.js

@@ -2,7 +2,6 @@
 'use strict';
 
 var async = require('async');
-var nconf = require('nconf');
 var S = require('string');
 var winston = require('winston');
 

src/upgrades/1.5.3/generate-email-logo.js

@@ -1,14 +1,11 @@
 'use strict';
 
-var db = require('../../database');
 var image = require('../../image');
 var meta = require('../../meta');
 
 var async = require('async');
-var winston = require('winston');
 var path = require('path');
 var nconf = require('nconf');
-var url = require('url');
 
 module.exports = {
 	name: 'Generate email logo for use in email header',