Fixed "keepalive_disable".

Patch by Alexander Usov.  The bug has been introduced in r4267.
diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index ba51910..96be423 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -3267,12 +3267,12 @@
      *     clcf->auto_redirect = 0;
      *     clcf->alias = 0;
      *     clcf->gzip_proxied = 0;
+     *     clcf->keepalive_disable = 0;
      */
 
     clcf->client_max_body_size = NGX_CONF_UNSET;
     clcf->client_body_buffer_size = NGX_CONF_UNSET_SIZE;
     clcf->client_body_timeout = NGX_CONF_UNSET_MSEC;
-    clcf->keepalive_disable = NGX_CONF_UNSET_UINT;
     clcf->satisfy = NGX_CONF_UNSET_UINT;
     clcf->if_modified_since = NGX_CONF_UNSET_UINT;
     clcf->max_ranges = NGX_CONF_UNSET_UINT;