SSL: fixed potential leak on memory allocation errors. If ngx_pool_cleanup_add() fails, we have to clean just created SSL context manually, thus appropriate call added. Additionally, ngx_pool_cleanup_add() moved closer to ngx_ssl_create() in the ngx_http_ssl_module, to make sure there are no leaks due to intermediate code.

--- a/src/stream/ngx_stream_proxy_module.c
+++ b/src/stream/ngx_stream_proxy_module.c
@@ -2096,6 +2096,7 @@ ngx_stream_proxy_set_ssl(ngx_conf_t *cf,
 
     cln = ngx_pool_cleanup_add(cf->pool, 0);
     if (cln == NULL) {
+        ngx_ssl_cleanup_ctx(pscf->ssl);
         return NGX_ERROR;
     }