fix highly unlikely bug

src/http/modules/ngx_http_log_module.c

diff --git a/src/http/modules/ngx_http_log_module.c b/src/http/modules/ngx_http_log_module.c
index c035449..04ba03b 100644
--- a/src/http/modules/ngx_http_log_module.c
+++ b/src/http/modules/ngx_http_log_module.c
@@ -546,6 +546,8 @@
                 return NGX_CONF_ERROR;
             }
 
+            log->disk_full_time = 0;
+
             lmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_log_module);
             fmt = lmcf->formats.elts;