Cleaned up duplicate middleware

refs 621cfd9866

- this file was meant to be moved to a folder in the referenced commit,
  but that never happened
- this commit fixes that

ghost/core/core/server/web/admin/middleware.js

@@ -1,17 +0,0 @@
-const urlUtils = require('../../../shared/url-utils');
-
-function redirectAdminUrls(req, res, next) {
-    const subdir = urlUtils.getSubdir();
-    const ghostPathRegex = new RegExp(`^${subdir}/ghost/(.+)`);
-    const ghostPathMatch = req.originalUrl.match(ghostPathRegex);
-
-    if (ghostPathMatch) {
-        return res.redirect(urlUtils.urlJoin(urlUtils.urlFor('admin'), '#', ghostPathMatch[1]));
-    }
-
-    next();
-}
-
-module.exports = [
-    redirectAdminUrls
-];