low SSL handshake close notify alert error level

src/event/ngx_event_openssl.c

diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
index d4b565c..8ba3e8e 100644
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -1158,6 +1158,7 @@
         if (n == SSL_R_NO_SHARED_CIPHER
             || n == SSL_R_UNEXPECTED_MESSAGE
             || n == SSL_R_WRONG_VERSION_NUMBER
+            || n == 1000 /* SSL_R_SSLV3_ALERT_CLOSE_NOTIFY */
             || n == SSL_R_SSLV3_ALERT_CERTIFICATE_EXPIRED
             || n == SSL_R_SSLV3_ALERT_ILLEGAL_PARAMETER
             || n == SSL_R_TLSV1_ALERT_UNKNOWN_CA)