Fixed old naming standard splitted rar archive (close #2733).

Patch by ozvald (see #2733)
(cherry picked from commit f75fc278)

src/input/input.c

@@ -2990,7 +2990,7 @@ static void InputGetExtraFiles( input_thread_t *p_input,
         { ".part1.rar",   "%s.part%.1d.rar",2, 9 },
         { ".part01.rar",  "%s.part%.2d.rar",2, 99, },
         { ".part001.rar", "%s.part%.3d.rar",2, 999 },
-        { ".rar",         "%s.r%.2d",       1, 99 },
+        { ".rar",         "%s.r%.2d",       0, 99 },
         { NULL, NULL, 0, 0 }
     };