A request body now might have up to two references

since d4b6228e the busyobj might also
gain one, so depending on who deref's first, there may be one or zero
references left.

bin/varnishd/cache/cache_req_body.c

@@ -263,11 +263,17 @@ VRB_Ignore(struct req *req)
 void
 VRB_Free(struct req *req)
 {
+	int r;
 
 	CHECK_OBJ_NOTNULL(req, REQ_MAGIC);
 
-	if (req->body_oc != NULL)
-		AZ(HSH_DerefObjCore(req->wrk, &req->body_oc, 0));
+	if (req->body_oc == NULL)
+		return;
+
+	r = HSH_DerefObjCore(req->wrk, &req->body_oc, 0);
+
+	// a busyobj may have gained a reference
+	assert (r == 0 || r == 1);
 }
 
 /*----------------------------------------------------------------------