Fixed "expires @time" with unknown last modified time (ticket #32).

src/http/modules/ngx_http_headers_filter_module.c

diff --git a/src/http/modules/ngx_http_headers_filter_module.c b/src/http/modules/ngx_http_headers_filter_module.c
index 8524450..c846c5f 100644
--- a/src/http/modules/ngx_http_headers_filter_module.c
+++ b/src/http/modules/ngx_http_headers_filter_module.c
@@ -262,16 +262,16 @@
 
     now = ngx_time();
 
-    if (conf->expires == NGX_HTTP_EXPIRES_ACCESS
-        || r->headers_out.last_modified_time == -1)
+    if (conf->expires == NGX_HTTP_EXPIRES_DAILY) {
+        expires_time = ngx_next_time(conf->expires_time);
+        max_age = expires_time - now;
+
+    } else if (conf->expires == NGX_HTTP_EXPIRES_ACCESS
+               || r->headers_out.last_modified_time == -1)
     {
         expires_time = now + conf->expires_time;
         max_age = conf->expires_time;
 
-    } else if (conf->expires == NGX_HTTP_EXPIRES_DAILY) {
-        expires_time = ngx_next_time(conf->expires_time);
-        max_age = expires_time - now;
-
     } else {
         expires_time = r->headers_out.last_modified_time + conf->expires_time;
         max_age = expires_time - now;