decrease log level from alert to debug for POLLERR|POLLHUP|POLLNVAL

src/event/modules/ngx_devpoll_module.c

diff --git a/src/event/modules/ngx_devpoll_module.c b/src/event/modules/ngx_devpoll_module.c
index 1ea51f9..e8135b9 100644
--- a/src/event/modules/ngx_devpoll_module.c
+++ b/src/event/modules/ngx_devpoll_module.c
@@ -416,7 +416,7 @@
                        event_list[i].fd, event_list[i].events, revents);
 
         if (revents & (POLLERR|POLLHUP|POLLNVAL)) {
-            ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,
+            ngx_log_debug2(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                           "ioctl(DP_POLL) error fd:%d ev:%04Xd rev:%04Xd",
                           event_list[i].fd, event_list[i].events, revents);
         }

src/event/modules/ngx_eventport_module.c

diff --git a/src/event/modules/ngx_eventport_module.c b/src/event/modules/ngx_eventport_module.c
index ebfd9a5..bd046ed 100644
--- a/src/event/modules/ngx_eventport_module.c
+++ b/src/event/modules/ngx_eventport_module.c
@@ -467,9 +467,9 @@
                            event_list[i].portev_object, revents);
 
             if (revents & (POLLERR|POLLHUP|POLLNVAL)) {
-                ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,
-                              "port_getn() error fd:%d ev:%04Xd",
-                              event_list[i].portev_object, revents);
+                ngx_log_debug2(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
+                               "port_getn() error fd:%d ev:%04Xd",
+                               event_list[i].portev_object, revents);
             }
 
             if (revents & ~(POLLIN|POLLOUT|POLLERR|POLLHUP|POLLNVAL)) {