Fixed Non-ASCII attachment filename will crash when downloading.

Thanks to xet7 !

Fixes #2759

packages/wekan-request/tests/test-toJSON.js

@@ -0,0 +1,14 @@
+var request = require('../index')
+  , http = require('http')
+  , assert = require('assert')
+  ;
+
+var s = http.createServer(function (req, resp) {
+  resp.statusCode = 200
+  resp.end('asdf')
+}).listen(8080, function () {
+  var r = request('http://localhost:8080', function (e, resp) {
+    assert.equal(JSON.parse(JSON.stringify(r)).response.statusCode, 200)
+    s.close()
+  })
+})