Referencing nginx base image in voltha values.yaml

Change-Id: Iacf25838057f9f8fab2633ba17c1c2a3dc19255c
diff --git a/voltha/templates/60-cluster-ingress-nginx.yaml b/voltha/templates/60-cluster-ingress-nginx.yaml
index 62fba3f..98517ee 100644
--- a/voltha/templates/60-cluster-ingress-nginx.yaml
+++ b/voltha/templates/60-cluster-ingress-nginx.yaml
@@ -37,8 +37,8 @@
         - sh
         - -c
         - sysctl -w net.core.somaxconn=32768; sysctl -w net.ipv4.ip_local_port_range="1024 65535"
-        image: alpine:3.6
-        imagePullPolicy: Always
+        image: {{ .Values.global.registry }}{{ .Values.images.ingress_controller_base.repository }}:{{ tpl .Values.images.ingress_controller_base.tag . }}
+        imagePullPolicy: {{ .Values.images.ingress_controller_base.pullPolicy }}
         name: sysctl
         securityContext:
           privileged: true