Regardless of whether "installpkg" command exists or not, install the
command temporarily with static linked tar command into the lxc cache
directory to keep the original uid/gid of files/directories.  Also,
use sed command instead of ed command for simplicity.
Signed-off-by: TAMUKI Shoichi <tamuki@linet.gr.jp>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>