Fixed an error log message about epoll_wait() timeout.

The errno value is unset in case of epoll_wait() timeout.

src/event/modules/ngx_epoll_module.c

diff --git a/src/event/modules/ngx_epoll_module.c b/src/event/modules/ngx_epoll_module.c
index 0b23a95..b1e520b 100644
--- a/src/event/modules/ngx_epoll_module.c
+++ b/src/event/modules/ngx_epoll_module.c
@@ -1000,8 +1000,8 @@
         ngx_use_epoll_rdhup = ee.events & EPOLLRDHUP;
 
     } else {
-        ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
-                      "epoll_wait() timedout");
+        ngx_log_error(NGX_LOG_ALERT, cycle->log, NGX_ETIMEDOUT,
+                      "epoll_wait() timed out");
     }
 
     ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0,