[Ansible] Adding new CentOS repo for newest Kubernetes packages.

contrib/ansible/roles/common/files/virt7-docker-common-candidate.repo

+[virt7-docker-common-candidate]
+name=virt7-docker-common-candidate
+baseurl=http://cbs.centos.org/repos/virt7-docker-common-candidate/x86_64/os/
+enabled=0
+gpgcheck=0

contrib/ansible/roles/common/tasks/centos.yml

 ---
-- name: CentOS | Install Testing centos7 repo for new tool versions
+- name: CentOS | Install Testing centos7 repo
   copy: src=virt7-testing.repo dest=/etc/yum.repos.d/virt7-testing.repo
+
+- name: CentOS | Install docker-common-candidate centos7 repo
+  copy: src=virt7-docker-common-candidate.repo dest=/etc/yum.repos.d/virt7-docker-common-candidate.repo

contrib/ansible/roles/master/tasks/centos.yml

 ---
-- name: CentOS | Install kubernetes CentOS style
+- name: CentOS | Install kubernetes master 
   yum:
     pkg=kubernetes-master
     state=latest
-    enablerepo=virt7-testing
+    enablerepo=virt7-docker-common-candidate
   notify:
     - restart daemons

contrib/ansible/roles/node/tasks/centos.yml

 ---
-- name: CentOS | Install kubernetes CentOS style
-  yum: pkg=kubernetes-node state=latest enablerepo=virt7-testing
+- name: CentOS | Install kubernetes node
+  yum:
+    pkg=kubernetes-node
+    state=latest
+    enablerepo=virt7-docker-common-candidate
   notify:
     - restart daemons