Mail: removed surplus ngx_close_connection() call.

It is already called for a peer connection a few lines above.

src/mail/ngx_mail_auth_http_module.c

diff --git a/src/mail/ngx_mail_auth_http_module.c b/src/mail/ngx_mail_auth_http_module.c
index 2e9b9f2..8094bbc 100644
--- a/src/mail/ngx_mail_auth_http_module.c
+++ b/src/mail/ngx_mail_auth_http_module.c
@@ -699,7 +699,6 @@
 
                     p = ngx_pnalloc(s->connection->pool, ctx->err.len);
                     if (p == NULL) {
-                        ngx_close_connection(ctx->peer.connection);
                         ngx_destroy_pool(ctx->pool);
                         ngx_mail_session_internal_server_error(s);
                         return;