Remove docker excluder from image prep packages

Given the choice of container runtime, docker and the docker excluder
should not be installed by default.  Container runtime installation is
handled by the container_runtime role.

Updated the package installation task to perform the install in one
transaction for the package list.

roles/openshift_node/defaults/main.yml

@@ -45,10 +45,8 @@ openshift_node_syscon_add_mounts_l: []
 
 default_r_openshift_node_image_prep_packages:
 - "{{ openshift_service_type }}-node"
-- "{{ openshift_service_type }}-docker-excluder"
 - ansible
 - bash-completion
-- docker
 - dnsmasq
 - ntp
 - logrotate

roles/openshift_node/tasks/install_rpms.yml

@@ -1,9 +1,8 @@
 ---
 - name: install needed rpm(s)
   package:
-    name: "{{ item }}"
+    name: "{{ r_openshift_node_image_prep_packages  | join(',') }}"
     state: present
-  with_items: "{{ r_openshift_node_image_prep_packages }}"
   register: result
   until: result is succeeded
   when: not (openshift_is_atomic | default(False) | bool)