Use common package install via variables rather than hard code the task

vars/CentOS-6-default.yml

@@ -0,0 +1,22 @@
+---
+# vars file for ensure_ansible_prereq
+package_list:
+  - name: 'acpid'
+    state: 'present'
+  - name: 'libselinux-python'
+    state: 'present'
+  - name: 'libsemanage-python'
+    state: 'present'
+  - name: 'pyOpenSSL'
+    state: 'present'
+  - name: 'python-pyasn1'
+    state: 'present'
+  - name: 'python-urllib3'
+    state: 'present'
+  - name: 'python2-ndg_httpsclient'
+    state: 'present'
+service_list:
+  - name: 'acpid'
+    state: 'started'
+    enabled: 'yes'
+