another when: not ansible_check_mode addition

If nginx is not yet installed, these will fail in check mode.

handlers/main.yml

@@ -1,6 +1,7 @@
 ---
 - name: restart nginx
   service: name=nginx state=restarted
+  when: not ansible_check_mode
 
 - name: validate nginx configuration
   command: nginx -t -c /etc/nginx/nginx.conf
@@ -8,3 +9,4 @@
 
 - name: reload nginx
   service: name=nginx state=reloaded
+  when: not ansible_check_mode