[options] Add --fragment-retries option

youtube_dl/options.py

@@ -399,6 +399,10 @@ def parseOpts(overrideArguments=None):
         '-R', '--retries',
         dest='retries', metavar='RETRIES', default=10,
         help='Number of retries (default is %default), or "infinite".')
+    downloader.add_option(
+        '--fragment-retries',
+        dest='fragment_retries', metavar='RETRIES', default=10,
+        help='Number of retries for a fragment (default is %default), or "infinite" (DASH only)')
     downloader.add_option(
         '--buffer-size',
         dest='buffersize', metavar='SIZE', default='1024',