fixes theme screenshots in acp

src/controllers/admin/themes.js

@@ -6,7 +6,7 @@ var fs = require('fs');
 var themesController = {};
 
 themesController.get = function(req, res, next) {
-	var themeDir = path.join(__dirname, '../../node_modules/' + req.params.theme);
+	var themeDir = path.join(__dirname, '../../../node_modules/' + req.params.theme);
 	fs.exists(themeDir, function(exists) {
 		if (exists) {
 			var themeConfig = require(path.join(themeDir, 'theme.json')),
@@ -14,7 +14,7 @@ themesController.get = function(req, res, next) {
 			if (themeConfig.screenshot && fs.existsSync(screenshotPath)) {
 				res.sendFile(screenshotPath);
 			} else {
-				res.sendFile(path.join(__dirname, '../../public/images/themes/default.png'));
+				res.sendFile(path.join(__dirname, '../../../public/images/themes/default.png'));
 			}
 		} else {
 			return next();