Fixed Non-ASCII attachment filename will crash when downloading.

Thanks to xet7 !

Fixes #2759

packages/wekan-request/tests/test-node-debug.js

@@ -0,0 +1,26 @@
+var assert = require('assert')
+  , request = require('../index')
+  , http = require('http')
+  ;
+
+var s = http.createServer(function(req, res) {
+  res.statusCode = 200
+  res.end('')
+}).listen(6767, function () {
+  // a simple request should not fail with NODE_DEBUG
+  process.env.NODE_DEBUG = 'mumblemumble,request'
+
+  var stderr = ''
+  process.stderr.write = (function(write) {
+    return function(string, encoding, fd) {
+      stderr += string
+    }
+  })(process.stderr.write)
+
+  request('http://localhost:6767', function (err, resp, body) {
+    assert.ifError(err, 'the request did not fail')
+    assert.ok(resp, 'the request did not fail')
+    assert.ok(/REQUEST/.test(stderr), 'stderr has some messages')
+    s.close(); // clean up
+  })
+})