Merge remote-tracking branch 'public/feature21496'

  o Minor features (safety):

    - Add an explict check to extrainfo_parse_entry_from_string() for NULL

      inputs. We don't believe this can actually happen, but it may help

      silence a warning from the Clang analyzer. Closes ticket 21496.

   * parse that's covered by the hash. */

  int can_dl_again = 0;

  if (BUG(s == NULL))

    return NULL;

  if (!end) {

    end = s + strlen(s);

  }