Fix compatibility with nginx-1.0.1.

Reported by Sergey A. Osokin.

Author: PiotrSikora

ngx_cache_purge_module.c

@@ -684,7 +684,11 @@ ngx_http_file_cache_purge(ngx_http_request_t *r, ngx_http_file_cache_t *cache,
         return NGX_DECLINED;
     }
 
+#  if defined(nginx_version) && (nginx_version >= 10001)
+    cache->sh->size -= c->node->fs_size;
+#  else
     cache->sh->size -= (c->node->length + cache->bsize - 1) / cache->bsize;
+#  endif
 
     c->node->exists = 0;
 #  if defined(nginx_version) \