Newer distros, such as debian jessie and ubuntu xenial, do not provide
ifupdown by default, but simple-init depends on it. Add it to the pile.
Change-Id: I6f4876863c67c65a82464d4e0593015cdc839c5c
Adds a post-install function that enables installed initscripts,
as that is not done by default in gentoo.
Change-Id: I04e8d506ddcbefa8a983dd31ad16df5e13cb26e7
Closes-Bug: 1539276