fix the ELASTICSEARCH_URL for kibana

roles/openshift_logging_kibana/templates/5.x/kibana.j2

@@ -60,7 +60,7 @@ spec:
 {%   endif %}
 {% endif %}
           env:
-            - name: "ES_URL"
+            - name: "ELASTICSEARCH_URL"
               value: "https://{{ es_host }}:{{ es_port }}"
             -
               name: "KIBANA_MEMORY_LIMIT"