build: Remove --enable-embedded-dependencies

This is going to bitrot too much; we'll figure out a better way to do
this when someone if a RHEL6 port ever happens.  Probably Software
Collections.
os-init: don't create /var/log/journal on deploy

Leave the policy of whether to persistently store journal logs to the
system integrator when the default journald configuration is in use.

https://bugzilla.gnome.org/show_bug.cgi?id=728762
WIP: Static deltas

This is a large code drop to support static deltas.  To be rebased.
deltas: Add support for LZMA compression

I got 30% better compression than gzip for my main static delta test
case, and that will likely improve more once we do better clustering.