VOL-1797 - fix helm lint issues

Change-Id: I74ccff1f7f431e05fc3963d0707382f478a010f0
diff --git a/voltha/templates/ro-core.yaml b/voltha/templates/ro-core.yaml
index b7cbb42..ce4a6bd 100644
--- a/voltha/templates/ro-core.yaml
+++ b/voltha/templates/ro-core.yaml
@@ -51,7 +51,7 @@
       serviceAccountName: {{ .Values.serviceaccount }}
       containers:
         - name: voltha
-          image: {{ tpl .Values.images.ro_core.registry . }}{{ tpl .Values.images.ro_core.repository . }}:{{ tpl .Values.images.ro_core.tag . }}
+          image: {{ tpl .Values.images.ro_core.registry . }}{{ tpl .Values.images.ro_core.repository . }}:{{ tpl ( tpl .Values.images.ro_core.tag . ) . }}
           imagePullPolicy: {{ tpl .Values.images.ro_core.pullPolicy . }}
           env:
             - name: NAMESPACE