Fix order of COLD events for directors vs. VCL

vcldir_retire() only sends a VCL_EVENT_COLD when the vcl is warm. In
other words, it (rightly) asserts that a COLD event (if any) has
alrady been posted when a director is deleted on a COLD vcl.

Yet, when the director is deleted upon a COLD vmod event, this assertion
was wrong, because the COLD events for directors were only posted after
vmod events.

Given that vmods do things like deleting directors, it appears (more)
correct to post VDI COLD events before VMOD COLD events.

bin/varnishd/cache/cache_vcl.c

@@ -594,9 +594,9 @@ vcl_set_state(struct vcl *vcl, const char *state, struct vsb **msg)
 		if (vcl->busy == 0 && vcl->temp->is_warm) {
 			vcl->temp = VTAILQ_EMPTY(&vcl->ref_list) ?
 			    VCL_TEMP_COLD : VCL_TEMP_COOLING;
+			vcl_BackendEvent(vcl, VCL_EVENT_COLD);
 			AZ(vcl_send_event(vcl, VCL_EVENT_COLD, msg));
 			AZ(*msg);
-			vcl_BackendEvent(vcl, VCL_EVENT_COLD);
 		}
 		else if (vcl->busy)
 			vcl->temp = VCL_TEMP_BUSY;

include/vrt.h

@@ -59,6 +59,7 @@
  *
  * NEXT (2024-03-15)
  *	[cache.h] (struct req).filter_list renamed to vdp_filter_list
+ *	order of vcl/vmod and director COLD events reversed to directors first
  * 18.1 (2023-12-05)
  *	vbf_objiterate() implementation changed #4013
  * 18.0 (2023-09-15)