update yum config

tasks/with_proxy.yml

diff --git a/tasks/with_proxy.yml b/tasks/with_proxy.yml
index c0b78f0..f8cb649 100644
--- a/tasks/with_proxy.yml
+++ b/tasks/with_proxy.yml
@@ -34,25 +34,7 @@
   yum:
     name: "{{ item }}"
     state: present
-  with_items:
-  - bind-utils
-  - chkconfig
-  - curl
-  - tar
-  - wget
-  - yum-utils
-  - unzip
-  - rsync
-  - which
-  - libselinux-python
-  - nss
-  - openssh-clients
-  - openssh-server
-  - grep
-  - rpm
-  - rng-tools
-  - sed
-  - unzip
+  with_items: "{{ yum_os_minimum_packages }}"
   environment:
     http_proxy: "{{ http_proxy }}"
     https_proxy: "{{ https_proxy }}"