sudo is not needed, since in-chroot elements are run in the context
of the root user. Furthermore, sudo in pre-install is problematic as
sudo may not have been installed yet (imagine a debootstrap build)
Change-Id: Ib5c7e176a90fe3b8fa9c3cd702d3d815df54f472
When using the yum element, we should reset the changes we've made to
/etc/yum.conf during post-install.d. Otherwise, this build time
configuration is propagated into booted instances.
Change-Id: I1eea586ca0fefe9bc0cf91fedefcbd141a536fa2
