Fix a bug in the previous commit

Hm, commit 3a7c9b3a02893ab9ac39e23cae5ead9e42716927 produced
good-looking debugging messages, but the required space was not
really updated.

Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Remove root= and resume= from the kdump kernel command line

Resume from hibernation should never be even attempted in kdump.
If using dracut, the module is even omitted from the initrd, so
passing the command line option only consumes command line space.

The default root device is not needed either, because all required
filesystems are handled by the mount dracut module. In fact, if the
root filesystem is also mounted, it may be mounted twice.

Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Dracut-systemd support

Adjust the dracut module to work with the systemd module.

A new service is added to the initrd. I could not use a pre-pivot
hook, because dracut-pre-pivot.service does not send the output
to the terminal, so dump progress was not visible.

It is also necessary to avoid mounting the root filesystem. All
filesystems needed by kdump are mounted under /kdump and set up
with the --mount dracut option.

The system root mount can be generated in two ways:

a. by initrd-fstab-generator (if "root=" is passed on the kernel
   command line)

b. by dracut-rootfs-generator (if the root option is stored in
   /etc/cmdline.d/*)

The root= parameter is already removed from the command line, but
it is always saved to /etc/cmdline.d/95root-dev.conf if dracut is
called with --hostonly-cmdline. This is the default in SLES (cf.
/etc/dracut.conf.d/01-dist.conf) and it is required to get correct
configuration for many setups.

So, the only way to avoid mounting /sysroot is to remove the
appropriate systemd generator from the initrd.

Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Calibrate: update user-space run-time requirements for systemd

If systemd is included, journald is also started, so the estimate
must add:

1. the process
2. the journal, which is stored in ramfs

I would love to reduce the size of the journal, but systemd hard-codes
the minimum to 4M, see src/journal/journal-file.c:

/* This is the minimum journal file size */
#define JOURNAL_FILE_SIZE_MIN (4ULL*1024ULL*1024ULL)           /* 4 MiB */

Strictly speaking, journald is allowed to use at least twice as much,
but let's hope it doesn't in practice.

Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Calibrate: update the initramfs size

Yes, systemd also needs some space in the initramfs, causing approx.
20% increase. Let's account for it...

Signed-off-by: Petr Tesarik <ptesarik@suse.cz>