This is not a complete fix for the problem that Info doen't propigate
from the called property when code does something like:
do
hostname <- asks hostName
ensureProperty $ foo hostname
Instead, I just eliminated the need to implement hasPassword that way,
by making the PrivData Info use a HostContext which automatically
gets the right hostname passed to it.
All other uses of withPrivData don't have the problem. It's still possible
for the user to run into the problem if they write something like the
above, where foo is a property that uses privdata. However, all properties
that take a Context now also accept a HostContext, so it's at least less
likely the user needs to write that.
This avoids leaving the system in a broken state where some directories
have been renamed away any others not.
Future work: If the rename list contains (foo, bar) and (newfoo,foo),
reorder the list to gather those two actions together to minimize
the amount of time that foo is missing. In case of power loss or something.
Particularly, the Makefile would try to build propellor if there were
updates, but if this build failed because a bad commit was pushed, it would
abort w/o pulling any new fixed commits.
Anyway, it's better to move away from using the makefile when possible as
it's just for bootstrapping, and also I would like to make "make" not
default to running propellor as that can be confusing behavior.
(I can't change that yet; needed for upgrades. Should be fine to change
after several more releases, or maybe a year..)