[4.1] 5e21eb3 VMODs handling of VCL_EVENT_COLD must be failsafe

[Lasse Karstensen]

commit 5e21eb3b915080c1a770a5f57fdce94ae188578a
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Tue Dec 1 15:48:38 2015 +0100

    VMODs handling of VCL_EVENT_COLD must be failsafe
    
    Also for 4.1

diff --git a/bin/varnishd/cache/cache_vcl.c b/bin/varnishd/cache/cache_vcl.c
index c747ead..de39d60 100644
--- a/bin/varnishd/cache/cache_vcl.c
+++ b/bin/varnishd/cache/cache_vcl.c
@@ -404,7 +404,7 @@ vcl_set_state(struct vcl *vcl, const char *state)
 			break;
 		if (vcl->busy == 0) {
 			vcl->temp = vcl_temp_cold;
-			(void)vcl->conf->event_vcl(&ctx, VCL_EVENT_COLD);
+			AZ(vcl->conf->event_vcl(&ctx, VCL_EVENT_COLD));
 			vcl_BackendEvent(vcl, VCL_EVENT_COLD);
 		} else {
 			vcl->temp = vcl_temp_cooling;