Properties now form a tree, instead of the flat list used before.
This simplifies propigation of Info from the Properties used inside a
container to the outer host; the Property that docks the container on the
host can just have as child properties all the inner Properties, and their
Info can then be gathered recursively. (Although in practice it still needs
to be filtered, since not all Info should propigate out of a container.)
Note that there is no change to how Properties are actually satisfied.
Just because a Property lists some child properties, this does not mean
they always have their propertySatisfy actions run. It's still up to the
parent property to run those actions.
That's necessary so that a container's properties can be satisfied inside
it, not outside. It also allows property combinators to
add the combined Properties to their childProperties list, even if,
like onChange, they don't always run the child properties at all.
Testing: I tested that the exact same Info is calculated before and after
this change, for every Host in my config file.
Lock a lock file while provisioning inside, otherwise propellor could be
running to init the container when the system has just booted, or the
container was just started from being stopped, and at the same time,
propellor run outside the container chains into it to provision.
Previously, simplesh prevented this in a different way.
The SetAttr hack used to be needed because the hostname was part of the
Attr, and was required to be present. Now that it's moved to Host, let's
get rid of that, since it tended to waste CPU.
This is to work around OSX's brain-damange regarding filename case
insensitivity.
Avoided moving config.hs, because it's a config file. Put in a symlink to
make build work.