fix python 2 urllib/urllib2 compatibility

update_plugins.py

@@ -2,15 +2,20 @@ try:
     import concurrent.futures as futures
 except ImportError:
     try:
-        import futures
+        import futures  # type: ignore
     except ImportError:
-        futures = None
+        futures = None # type: ignore
+
+try:
+    from urllib.request import urlopen
+except ImportError:
+    from urllib2 import urlopen # type: ignore
 
 import re
 import shutil
 import tempfile
-import urllib.request
 import zipfile
+from contextlib import closing
 from io import BytesIO
 from os import listdir, path
 
@@ -73,7 +78,7 @@ SOURCE_DIR = path.join(path.dirname(__file__), "sources_non_forked_cache")
 
 def download_extract_replace(plugin_name, zip_path, temp_dir, source_dir):
     # Download and extract file in temp dir
-    with urllib.request.urlopen(zip_path) as req:
+    with closing(urlopen(zip_path)) as req:
         zip_f = zipfile.ZipFile(BytesIO(req.read()))
         zip_f.extractall(temp_dir)
         content_disp = req.headers.get("Content-Disposition")