Respect outbound HTTP setting in macro generation

Summary: We respect this when adding inputs to the form, but not when guarding the actual fetch.

Test Plan: Reading

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D12030

src/applications/macro/controller/PhabricatorMacroEditController.php

@@ -67,7 +67,7 @@ final class PhabricatorMacroEditController extends PhabricatorMacroController {
             'isExplicitUpload' => true,
             'canCDN' => true,
           ));
-      } else if ($request->getStr('url')) {
+      } else if ($request->getStr('url') && $can_fetch) {
         try {
           $file = PhabricatorFile::newFromFileDownload(
             $request->getStr('url'),