Description of problem:

The die() function halts the system on error:
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
 447 die() {
 :
 467     if [ -n "$DRACUT_SYSTEMD" ]; then
 468         systemctl --no-block --force halt
 469     fi
 470 
 471     exit 1
 472 }
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

Halting the system doesn't poweroff the system, which should let the user understand what's going on.
Unfortunately, on many real hardware, including Lenovo T460s, it appears that as soon as the system is halted, the display is powered off, preventing the user from seeing the reason for dracut dying.

This is particularly annoying when the user tries to boot a RHEL ISO which appears to be corrupted: the corruption is detected and immediately after the display goes blank.

I'm proposing to add a 30 seconds delay before halting, which should be sufficient, something like this below:
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
 447 die() {
 448     {
 :
 467     if [ -n "$DRACUT_SYSTEMD" ]; then
 468         echo "<24>dracut: Halting the system in 30 seconds" > /dev/kmsg
 469         sleep 30
 470         echo "<24>dracut: Halting the system" > /dev/kmsg
 471         systemctl --no-block --force halt
 472     fi
 :
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

We could do better, such as asking the user to confirm through hitting Enter, but it's more complicated to implement, since it requires spawning a one-shot service that takes control of the console.

Version-Release number of selected component (if applicable):

dracut-057

How reproducible:

Always

Steps to Reproduce:
1. Corrupt a RHEL ISO

  # dd if=/dev/zero of=/path/to/iso seek=200M count=10 bs=1 conv=notrunc

2. Boot the ISO on real hardware (QEMU/KVM doesn't reproduce because the screen doesn't blank)

  It reproduces on Lenovo T460s, ASUS Chromebook C202S, ASUS M415U Notebook and HP envy360 at least.

Actual results:

Corruption detection message + screen blanking immediately after

Expected results:

Corruption detection message + screen not blanking