Centos 7 docker admin

This is the latest version of my centos 7 admin node series.

It includes the fixups I already have pull requests open for, along with these additional changes:

* Hack up the docker admin to allow systemd to run as a real init system while not also requiring that the container run in --privileged mode.
* Fix up the bootstrap recipes to use centos 7 while removing some of the worarounds we needed to fake having a working init.
* Ditch apache in favor of a tiny zero-configuration webserver.
* Ditch chef-server in favor of goiardi.  This lets me drop the hacks I had been using to run chef-server in a container, and lets us run with only one install of postgres.
* Build openwsman from source instead of from packages.  The upstream openwsman packages for RHEL/Centos 7 are out of date and not sufficient for our needs, and the ones from suse's OBS do not build.  Right now the install happens via make install
* Switch to using grub2 instead of pxelinux and elilo for our bootloaders.  This also custom compiles grub2 to add support for talking to http servers on ports other than 80, and it provides a useful upgrade path for netbooting x86 servers.