Add common Ubuntu packages to LXC image cache
Add common Ubuntu packages to LXC image cache

Several packages are installed in multiple different roles but they
could easily be placed in the image cache to save time and bandwidth.

These include:

  git             (10 roles install it)
  rsync           (9 roles install it)
  python-dev      (8 roles install it)
  build-essential (7 roles install it)

Change-Id: I6ad82e8a2227786afbb5056f33cbdbc9870e778c

os-cloud/openstack-ansible-lxc_hosts,os-cloud/openstack-ansible-lxc_hosts,openstack/openstack-ansible-lxc_hosts,openstack/openstack-ansible-lxc_hosts