Suppress curl warning w/shell module

Using curl from the shell module generates an Ansible warning.
This patch adds "warn: no" to suppress the warning.

Change-Id: I83a52173aea5e5574d4d1acee16ebad95845ff5e

playbooks/utility-install.yml

@@ -58,6 +58,8 @@
 
     - name: Get list of python clients
       shell: "curl -s {{ repo_release_path }}/requirements_absolute_requirements.txt  | grep client | cut -d'=' -f1"
+      args:
+        warn: no
       register: client_list
       run_once: true
       changed_when: false