Dump the controller log when the varnish_pod_template proxy test fails.

Since it has been failing consistently in the CI pipeline.

examples/varnish_pod_template/verify_proxy.sh

 #! /bin/bash -x
 
+function dump_controller_log {
+    echo "error status $?"
+    local pod=( $(kubectl get pods -n kube-system -l app=varnish-ingress-controller --no-headers -o custom-columns=":metadata.name") )
+    kubectl logs -n kube-system ${pod}
+}
+
 MYDIR=$(dirname ${BASH_SOURCE[0]})
 source ${MYDIR}/../../test/utils.sh
 
@@ -8,6 +14,7 @@ LOCALPORT=${LOCALPORT:-8888}
 wait_until_deleted app=varnish-ingress,example!=proxy
 
 set -e
+trap dump_controller_log ERR
 wait_until_ready example=proxy
 wait_until_configured example=proxy