Will be nice to clear auth credentials. For example, I'm using a proxy that accepts options via username:

```
proxy.com:8080
user: wiliam_country_US
```

So, if I want to change the peer node, I change my username:

```
proxy.com:8080
user: wiliam_country_GB
```

But, I'm not changing the proxy, so electron has valid credentials and is not going to trigger `login` event.

I'm searching the way to clean auth settings so electron asks them again.
atom/browser/api/atom_api_session.cc
content::DownloadItem* item) {
  if (item->IsSavePackageDownload())
    return;
  v8::Locker locker(isolate());
  v8::HandleScope handle_scope(isolate());
  auto handle = DownloadItem::Create(isolate(), item);
  if (item->GetState() == content::DownloadItem::INTERRUPTED)
    handle->SetSavePath(item->GetTargetFilePath());
  bool prevent_default = Emit("will-download", handle, item->GetWebContents());
  if (prevent_default) {
    item->Cancel(true);
    item->Remove();
  }
}
void Session::ResolveProxy(const GURL& url, ResolveProxyCallback callback) {
  new ResolveProxyHelper(browser_context(), url, callback);
}
template<Session::CacheAction action>
void Session::DoCacheAction(const net::CompletionCallback& callback) {
  BrowserThread::PostTask(BrowserThread::IO, FROM_HERE,
      base::Bind(&DoCacheActionInIO,
                 make_scoped_refptr(browser_context_->GetRequestContext()),
                 action,
                 callback));
}
void Session::ClearStorageData(mate::Arguments* args) {