include tcpdump in azure images

playbooks/azure/openshift-cluster/build_node_image.yml

@@ -24,6 +24,7 @@
       openshift_control_plane_static_pod_location: /etc/origin/node/disabled/
       openshift_node_image_prep_packages:
       - strace
+      - tcpdump
       etcd_ip: ETCD_IP_REPLACE
 
   - name: add insights-client to package installs when on rhel