Bug#945404: Information

[khimaros]

I don't believe this is a problem specific to NVMe, as my working machine has an NVMe drive.

The working installation is quite old as is the case with the reporter. The working machine was
upgraded in place from stretch. The original installation medium was:

```
# cat /var/log/installer/lsb-release 
DISTRIB_ID=Debian
DISTRIB_DESCRIPTION="Debian GNU/Linux installer"
DISTRIB_RELEASE="9 (stretch) - installer build 20170112"
X_INSTALLATION_MEDIUM=cdrom
```

I am able to reproduce the breakage with two other machines which have HDD. These machines were
installed more recently (most recent was two days ago), using the same netinst image over USB:

```
# cat /var/log/installer/lsb-release
DISTRIB_ID=Debian
DISTRIB_DESCRIPTION="Debian GNU/Linux installer"
DISTRIB_RELEASE="10 (buster) - installer build 20190702+deb10u2"
X_INSTALLATION_MEDIUM=cdrom
```

All three machines are now on buster and have grub-common=2.04-5. All three machines are laptops.

Below are the lines from `grub-probe -vv -t abstraction` which are only present on the working
machine:

```
grub-probe: info: changing current directory to block.
grub-probe: info: changing current directory to by-partuuid.
grub-probe: info: changing current directory to by-uuid.
grub-probe: info: changing current directory to disk.
grub-probe: info: cheatmounted hostdisk//dev/nvme0n1,msdos5 (luks) at /dev/mapper/nvme0n1p5_crypt.
grub-probe: info: no LVM signature found.
grub-probe: info: opening the device hostdisk//dev/nvme0n1.
grub-probe: info: Partition 0 starts from 2048.
grub-probe: info: Partition 4 starts from 501760.
grub-probe: info: scanning crypto0 for LDM.
grub-probe: info: Scanning for dmraid_nv devices on disk crypto0.
grub-probe: info: Scanning for ldm devices on disk crypto0.
grub-probe: info: Scanning for ldm devices on disk hostdisk//dev/nvme0n1.
```

To summarize, it seems that grub-probe is scanning a few more /dev paths, "cheatmounted" one of the
devices, and did not find an LVM signature on one of the devices. There are also several references
to a crypto0 device.

I've reinstalled one of the machines with RC3 of the buster installation media and had the same
issue. Partitioned as "Guided full disk LVM encrypted volume" -- accepted all defaults.