Remove [compute-feature-enabled] vnc_server_header

This option was deprecated some years back[1], and has had no effect
since the 22.0.0 release.

[1] fd01d15d144caa4d5a482301d05cf724c75c4500

Change-Id: Ib2ac35eec958153e139f2fcfee05c2d6aeb56e81
diff --git a/releasenotes/notes/remove-vnc-server-header-1a9731ba10242603.yaml b/releasenotes/notes/remove-vnc-server-header-1a9731ba10242603.yaml
new file mode 100644
index 0000000..cf14513
--- /dev/null
+++ b/releasenotes/notes/remove-vnc-server-header-1a9731ba10242603.yaml
@@ -0,0 +1,5 @@
+---
+upgrade:
+  - |
+    The deprecated ``[compute-feature-enabled] vnc_server_header`` option has
+    been removed.