Add ability to copy more files from LXC host into cache

When preparing the cache, it may be useful to copy more
files into the container cache prior to executing the
package installation. For example, an extra repo config
file may be needed.

This patch allows an optional extra list of files to be
added to the container cache in addition to the existing
set that this defined in vars.

Change-Id: I14a396cda8d1ad23f7ceb61e7867203013f50823

defaults/main.yml

@@ -102,13 +102,21 @@ lxc_cache_sshd_configuration:
 # The compression ratio used when creating the container cache rootfs archive
 lxc_image_compression_ratio: 0
 
-# A list of files may be copied into the container image cache during its preparation.
+# A list of files may be copied into the container image cache from the
+# deployment host during its preparation.
 # Example:
 #   lxc_container_cache_files:
 #     - src: "/etc/openstack_deploy/files/etc/issue"
 #       dest: "/etc/issue"
 lxc_container_cache_files: []
 
+# A list of files may be copied into the container image cache from the
+# LXC host during its preparation.
+# Example:
+#   lxc_container_cache_files_from_host:
+#     - "/etc/apt/sources.list.d/myrepo.list"
+lxc_container_cache_files_from_host: []
+
 # DNS servers to use during cache preparation
 lxc_cache_prep_dns:
   - "{{ lxc_net_address }}"

tasks/lxc_cache_preparation.yml

@@ -69,8 +69,6 @@
   when:
     - ansible_pkg_mgr == 'apt'
 
-# TODO(evrardjp): replace this with a copy with remote_src: True
-# when ansible2.0 will be supported
 - name: Rsyncing files from the LXC host to the container cache
   shell: |
     if [[ -e "{{ item }}" ]]; then
@@ -78,7 +76,7 @@
     fi
   args:
     executable: "/bin/bash"
-  with_items: "{{ lxc_cache_map.copy_from_host }}"
+  with_items: "{{ (lxc_cache_map.copy_from_host | union(lxc_container_cache_files_from_host)) | list }}"
   tags:
     - skip_ansible_lint