add centos 6.8 and centos 7.2

Author: chris-rock

.kitchen.yml

@@ -25,11 +25,19 @@ platforms:
 - name: centos-6.7
   driver:
     image: centos:6.7
+- name: centos-6.8
+  driver:
+    image: centos:6.8
 - name: centos-7
   driver:
     image: centos:7
     privileged: true
     run_command: /usr/sbin/init
+- name: centos-7.2
+  driver:
+    image: centos:7.2.1511
+    privileged: true
+    run_command: /usr/sbin/init
 - name: debian-7
   driver:
     image: debian:7