Add changes for 4.1.9

Prompted on irc by scn.

doc/changes.rst

@@ -522,6 +522,42 @@ News for Vmod Authors
 
 * PRIV_* now also work for object methods with unchanged scope.
 
+================================
+Varnish Cache 4.1.9 (2017-11-14)
+================================
+
+Changes since 4.1.8:
+
+* Added ``bereq.is_bgfetch`` which is true for background fetches.
+* Add the vtc feature ignore_unknown_macro.
+* Expose to VCL whether or not a fetch is a background fetch (bgfetch)
+* Ignore req.ttl when keeping track of expired objects (see 2422_)
+* Move a cli buffer to VSB (from stack).
+* Use a separate stack for signals.
+
+.. _2422: https://github.com/varnishcache/varnish-cache/pull/2422
+
+Bugs fixed
+----------
+
+* 2337_ and 2366_ - Both Upgrade and Connection headers are needed for
+  WebSocket now
+* 2372_ - Fix problem with purging and the n_obj_purged counter
+* 2373_ - VSC n_vcl, n_vcl_avail, n_vcl_discard are gauge
+* 2380_ - Correct regexp in examples.
+* 2390_ - Straighten locking wrt vcl_active
+* 2429_ - Avoid buffer read overflow on vcl_backend_error and -sfile
+* 2492_ - Use the idle read timeout only on empty requests
+
+.. _2337: https://github.com/varnishcache/varnish-cache/issues/2337
+.. _2366: https://github.com/varnishcache/varnish-cache/issues/2366
+.. _2372: https://github.com/varnishcache/varnish-cache/pull/2372
+.. _2373: https://github.com/varnishcache/varnish-cache/issues/2373
+.. _2380: https://github.com/varnishcache/varnish-cache/issues/2380
+.. _2390: https://github.com/varnishcache/varnish-cache/issues/2390
+.. _2429: https://github.com/varnishcache/varnish-cache/pull/2429
+.. _2492: https://github.com/varnishcache/varnish-cache/issues/2492
+
 ================================
 Varnish Cache 4.1.8 (2017-08-02)
 ================================