clean up 99-copy-logs.ks

Rather than changing the names of the logs or explicitly naming which
logs to copy, let's just copy syslog and all the logs in /tmp/*.log to
the target system.
Move systemd journal to disk once we have usable disks (#882132)

Saving the journal is a good idea - it has some log info that aren't in
our existing logs (dracut output, for example).

We could just make a copy of it at the end of the install.. but we can
also make the running journald move the active journal to the disk, by:

1) creating /var/log/journal (as a symlink to the disk), and
2) (re)starting systemd-journal-flush.service.

Doing it this way rather than copying it at the end saves some RAM and
gives us on-disk logs that will be there even if you yank the power cord
before we get to kickstart %post.

So: as soon as we're sure we've got somewhere persistent we can write to,
we should move the journal. At the moment where preInstall happens we
have the target disk mounted but there's nothing on it yet. This is
probably the earliest point where we can safely start writing to disk,
so that's when it happens.
dracut/parse-kickstart: handle network --mtu

Clean up the network handling a little bit, and add the mtu where dracut
expects to find it.
Fix console= persistence, remove serial (#928269)

The 'serial' option was supposed to have been removed, but it got left
behind in a few places. Somehow it mutated into an argument to keep the
user-set "console=XXX" argument in the installed system?

This patch should straighten things out to match the intended behavior:
* "serial" is deprecated and ignored; try "console=ttyS0" instead.
* If you use "console=XXX" it will be preserved in the installed system.
* If multiple "console=XXX" args are used, the *last* one is preserved.

It might be kind of useful to be able to override this but I really
can't think of a use case for that right now, so I'm leaving it out.
You can always just remove it with a sed oneliner¹ or something.

Here's what the patch actually changes:
- Adds iutil.get_active_console()
- Uses that to fix iutil.isConsoleOnVirtualTerminal()²
- Sets BootLoader.console whenever 'console=XXX' is present, instead of
  only when flags.serial is set
- Uses iutil.isConsoleOnVirtualTerminal() instead of flags.serial to
  determine when it's OK to use GRUB splash
- Removes flags.serial, since it's now completely unused.

¹ e.g. `sed 's/console=\S*\s*//' /etc/grub*.cfg`
² Note the "XXX PJFIX", which means pjones owes me a beer.
Cleanup: remove dead upgrade code

We don't support upgrades anymore. Preupgrade is gone. These leftover
attributes are unused and the code is unreachable.

Scrub it all clean, even the comments. NO SURVIVORS.