Verification script waits more robustly for port-forward connectivity.

XXX: re-use this code wherever we wait for port-forward.

deploy/verify.sh

@@ -16,5 +16,19 @@ kubectl port-forward svc/varnish-ingress ${LOCALPORT}:80 >/dev/null &
 KUBEPID=$!
 trap killforward EXIT
 
-sleep 1
+set +e
+N=0
+while true; do
+    sleep 1
+    cat < /dev/null > /dev/tcp/localhost/${LOCALPORT}
+    if [ $? -eq 0 ]; then
+        break
+    fi
+    if [ $N -ge 120 ]; then
+        echo "Giving up"
+        exit 1
+    fi
+    N=$(( N + 1 ))
+done
+set -e
 varnishtest ${TESTOPTS} -Dlocalport=${LOCALPORT} deploy.vtc