Do not re-download files for hashsum generation (Fixes #1383)

devscripts/gh-pages/add-version.py

@@ -23,10 +23,13 @@ filenames = {
     'bin': 'youtube-dl',
     'exe': 'youtube-dl.exe',
     'tar': 'youtube-dl-%s.tar.gz' % version}
+build_dir = os.path.join('..', '..', 'build', version)
 for key, filename in filenames.items():
-    print('Downloading and checksumming %s...' % filename)
-    url = 'https://yt-dl.org/downloads/%s/%s' % (version, filename)
-    data = urllib.request.urlopen(url).read()
+    fn = os.path.join(build_dir, filename)
+    with open(fn, 'rb') as f:
+        data = f.read()
+    if not data:
+        raise ValueError('File %s is empty!' % fn)
     sha256sum = hashlib.sha256(data).hexdigest()
     new_version[key] = (url, sha256sum)