the name created by the installer is different

This silences a warning when rebuilding the initrd.

howto/new-machine-cymru.md

@@ -225,7 +225,7 @@ point it becomes a bit too complicated.
 If you need to do something post-install, this should bring you a
 working shell in the `chroot`:
 
-    cryptsetup luksOpen /dev/sda3 crypt_sda3 &&
+    cryptsetup luksOpen /dev/sda3 crypt_dev_sda3 &&
     vgchange -a y &&
     mount /dev/mapper/vg_ganeti-root /mnt &&
     for fs in /run /sys /dev /proc; do mount -o bind $fs /mnt$fs; done &&
@@ -243,7 +243,7 @@ And this will cleanup the rest:
     for fs in /dev /sys /run /proc; do umount /mnt$fs; done &&
     umount /mnt &&
     vgchange -a n &&
-    cryptsetup luksClose crypt_sda3
+    cryptsetup luksClose crypt_dev_sda3
 
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