explicit close file on file:// scheme handler

scrapy/core/downloader/handlers/file.py

@@ -10,6 +10,7 @@ class FileDownloadHandler(object):
     @defers
     def download_request(self, request, spider):
         filepath = file_uri_to_path(request.url)
-        body = open(filepath, 'rb').read()
+        with open(filepath, 'rb') as fo:
+            body = fo.read()
         respcls = responsetypes.from_args(filename=filepath, body=body)
         return respcls(url=request.url, body=body)