[4.1] 0a800c5 It is OK to VCL_Ref a cooling VCL.

[Poul-Henning Kamp]

commit 0a800c5167b6e8ccd0df483bb69136c30199aac2
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Mon Aug 17 09:21:13 2015 +0000

    It is OK to VCL_Ref a cooling VCL.
    
    Fixes: #1776

diff --git a/bin/varnishd/cache/cache_vcl.c b/bin/varnishd/cache/cache_vcl.c
index 0d3ed42..e11cf01 100644
--- a/bin/varnishd/cache/cache_vcl.c
+++ b/bin/varnishd/cache/cache_vcl.c
@@ -163,7 +163,7 @@ VCL_Ref(struct vcl *vcl)
 {
 
 	CHECK_OBJ_NOTNULL(vcl, VCL_MAGIC);
-	assert(vcl->temp == vcl_temp_warm);
+	assert(vcl->temp == vcl_temp_warm || vcl->temp == vcl_temp_cooling);
 	Lck_Lock(&vcl_mtx);
 	assert(vcl->busy > 0);
 	vcl->busy++;