fix r2378, file inclusion should be waited

src/http/modules/ngx_http_ssi_filter_module.c

diff --git a/src/http/modules/ngx_http_ssi_filter_module.c b/src/http/modules/ngx_http_ssi_filter_module.c
index 74a2c85..849e13b 100644
--- a/src/http/modules/ngx_http_ssi_filter_module.c
+++ b/src/http/modules/ngx_http_ssi_filter_module.c
@@ -1881,6 +1881,7 @@
 
     if (uri == NULL) {
         uri = file;
+        wait = (ngx_str_t *) -1;
     }
 
     rc = ngx_http_ssi_evaluate_string(r, ctx, uri, NGX_HTTP_SSI_ADD_PREFIX);