[downloader/http] Fix access to not yet opened stream in retry

youtube_dl/downloader/http.py

@@ -223,6 +223,7 @@ class HttpFD(FileDownloader):
 
             def retry(e):
                 to_stdout = ctx.tmpfilename == '-'
+                if ctx.stream is not None:
                     if not to_stdout:
                         ctx.stream.close()
                     ctx.stream = None