Extend telegraf Openstack input plugin template

add region parameter

Change-Id: I034d442f5287d7814f21c0208dbaf8aee78cfab6
Related-PROD: PROD-24428 (PROD:24428)
diff --git a/telegraf/files/input/openstack.conf b/telegraf/files/input/openstack.conf
index 37ddc60..1109fa9 100644
--- a/telegraf/files/input/openstack.conf
+++ b/telegraf/files/input/openstack.conf
@@ -4,6 +4,9 @@
   username = "{{ values.username }}"
   password = "{{ values.password }}"
   identity_endpoint = "{{ values.identity_endpoint }}"
+{%- if values.region is defined %}
+  region = "{{ values.region }}"
+{%- endif %}
   monitor_agents = {{ values.monitor_agents|default("true")|lower }}
   cpu_ratio = {{ values.cpu_ratio|default(1.0) }}
 {%- include 'telegraf/files/input/_filters.conf' %}