Remove hard-coded externaldns image versions

Related story: https://mirantis.jira.com/browse/PROD-22456

Change-Id: I7a0eb61cfc85ac71adc287bb9ee33e8c47cf9e97
diff --git a/classes/cluster/sl-k8s-contrail/kubernetes/init.yml b/classes/cluster/sl-k8s-contrail/kubernetes/init.yml
index 6ad9e8c..fdc84c0 100644
--- a/classes/cluster/sl-k8s-contrail/kubernetes/init.yml
+++ b/classes/cluster/sl-k8s-contrail/kubernetes/init.yml
@@ -20,7 +20,7 @@
     kubernetes_pause_image: docker-prod-virtual.docker.mirantis.net/mirantis/kubernetes/pause-amd64:v1.11.2-1
     kubernetes_netchecker_agent_image: quay.io/l23network/k8s-netchecker-agent:v1.0
     kubernetes_netchecker_server_image: quay.io/l23network/k8s-netchecker-server:v1.0
-    kubernetes_externaldns_image: mirantis/external-dns:latest
+
     kubernetes_externaldns_provider: coredns
 
     # switches of addons