Fix buggy "persistence is not enabled" step.

It grep:ed for the wrong device (DM mappings are involved) so it would
pass even if persistence was disabled. Now this check uses the
persistence state file created by Tails Greeter in a way similar to
how tails-persistence-setup determines whether persistence is in use.
Also, this step's positive version now use the same approach, and both
steps were renamed to "is enabled/disabled" for greater consistency.

The old code for this step, which checks whether all persistent
directories have been successfully mounted, is put into a step of its
own, since it's still something we should test.
draft for explaining how to change persistence passphrase
system requirements rephrasing to explicitly includes Mac
unbolding things
Merge branch 'test/rjb-migration' into test/fix-persistence-checks
Robustness improvements: more quoting in shell commands, chain commands with &&.
Merge "all persistent directories are mounted" back into "persistence is enabled".

It's the kind of low-level implementation detail that makes it harder to read
and maintain features, and that should instead be hidden in step definitions.
It's probably not in these terms that a Tails user would express their
experience of the Tails persistence feature.
Merge branch 'test/rjb-migration' into test/fix-persistence-checks
Delete volumes after each scenario unless tagged @keep_volumes.

This makes scenario dependencies from volumes shared between them
pretty explicit (if scenario i is tagged, then scenario i + 1 depends
on scenario i), so we can remove the comment about that. It also helps
keeping the free disk space requirement down as volumes don't pile up
unnecessarily after they're not needed any more.
Finish backporting test/keep-volumes-tag to pre-test/reorg.

This will need to be reverted when we merge test/reorg.
new draft for change persistence passphrase doc
Set environment variables for the control port filter

This will cause Torbutton to enable the New Identity
feature, and attempt to request SIGNAL NEWNYM through
port 9052, where our control port filter will be.
Change firewall rules to allow access to the control port filter

This also removes the entry where amnesia user had
access to the real control port. This is of no use
as the amnesia user cannot authenticate anyway
(it cannot read the authcookie file).
Add the actual control port filter proxy

Written in python for simplicity and security.
The script is going to be run by the vidalia user,
which has access to the real Tor control port.
Add a startup script for the control port filter

The control port filter will be started as the vidalia user,
as the permissions it requires matches well with that of
the vidalia user.

It is always started, and does never need to be restarted.
If Tor is not running when a newnym request is made, it will
just return back an error message.
Update design documentation for the control port filter
Remove from known issues, it now works again
Drop the Tails Upgrader launcher, to limit users' confusion (Closes: #6513).
Create /var/run/tails-upgrader at boot time.

Tails Upgrader is run as a non-privileged user, so it cannot create its run
directory itself.
Use startswith instead to make functionality clearer