Fix calculation of cache filename length.

The calculation skipped some parts that are included in the filename.

src/libdvdcss.c

@@ -270,7 +270,8 @@ static char *set_cache_directory( dvdcss_t dvdcss )
         /* Check that there is enough space for the cache directory path and the
          * block filename. The +1 are path separators and terminating null byte. */
         else if( strlen( psz_cache ) + 1 + DISC_TITLE_LENGTH + 1 +
-                 STRING_KEY_SIZE + CACHE_FILENAME_LENGTH + 1 > PATH_MAX )
+                 MANUFACTURING_DATE_LENGTH + 1 + STRING_KEY_SIZE + 1 +
+                 CACHE_FILENAME_LENGTH + 1 > PATH_MAX )
         {
             print_error( dvdcss, "cache directory name is too long" );
             return NULL;