make auditsource a class

this allows us to use AuditSource for the class and auditSource for
the instances!

src/routes/network.js

@@ -6,7 +6,7 @@ exports = module.exports = {
 };
 
 const assert = require('assert'),
-    auditSource = require('../auditsource.js'),
+    AuditSource = require('../auditsource.js'),
     BoxError = require('../boxerror.js'),
     HttpError = require('connect-lastmile').HttpError,
     HttpSuccess = require('connect-lastmile').HttpSuccess,
@@ -27,7 +27,7 @@ async function setBlocklist(req, res, next) {
 
     req.clearTimeout(); // can take a while if there is a lot of network ranges
 
-    const [error] = await safe(network.setBlocklist(req.body.blocklist, auditSource.fromRequest(req)));
+    const [error] = await safe(network.setBlocklist(req.body.blocklist, AuditSource.fromRequest(req)));
     if (error) return next(BoxError.toHttpError(error));
 
     next(new HttpSuccess(200, {}));