Fix missing /run/resolvconf/resolv.conf in trusty/xenial

Ubuntu 14/16.04 uses links /etc/resolv.conf to
/run/resolvconf/resolv.conf.  This results in a
failure of rsync to copy the contents of the
lxc host's resolv.conf contents into the container
template, and only recreates the link.

This commit adds the necessary files from /run/resolvconf
to the container template to allow for proper domain
resolution during template modification.

The sync command from the tasks/lxc_cache_preparation.yml file
now ensures a source exists prior to running the sync. This is
needed because of differences in the gate vs what is seen in
production. Additionally the item variables in the sync command
have been quoted they can not be escaped.

Change-Id: I58c9a81306922f9e587e1ed3a7a2693c64bfec3c

tasks/lxc_cache_preparation.yml

@@ -25,7 +25,12 @@
 # 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
-  command: "rsync -a {{ item }} /var/lib/lxc/LXC_NAME/rootfs{{ item }}"
+  shell: |
+    if [[ -e "{{ item }}" ]]; then
+      rsync -av "{{ item }}" "/var/lib/lxc/LXC_NAME/rootfs{{ item }}"
+    fi
+  args:
+    executable: "/bin/bash"
   with_items: "{{ lxc_cache_map.copy_from_host }}"
   tags:
     - lxc-cache

vars/ubuntu-14.04.yml

@@ -44,6 +44,7 @@ lxc_cache_map:
     - /etc/apt/sources.list
     - /etc/apt/sources.list.d/
     - /etc/apt/apt.conf.d/
+    - /run/resolvconf/
     - /etc/resolvconf/
     - /etc/resolv.conf
     - /root/repo.keys

vars/ubuntu-16.04.yml

@@ -47,6 +47,7 @@ lxc_cache_map:
     - /etc/apt/sources.list
     - /etc/apt/sources.list.d/
     - /etc/apt/apt.conf.d/
+    - /run/resolvconf/
     - /etc/resolvconf/
     - /etc/resolv.conf
     - /root/repo.keys