Invalid config generated when using GRUB_EARLY_INITRD_LINUX_CUSTOM

[Jrandiny]

When trying to add GRUB_EARLY_INITRD_LINUX_CUSTOM options in /etc/default/grub the resulting grub.cfg become invalid

For example by adding

GRUB_EARLY_INITRD_LINUX_CUSTOM="acpi_override"

Result:
```
 initrd /boot/ acpi_override initrd.img-5.8.0-050800-generic
```

Expected:
```
 initrd /boot/acpi_override /boot/initrd.img-5.8.0-050800-generic

```

When comparing 10_linux script with other distro (Manjaro) it seems that the Ubuntu version doesn't account for multiple initrd

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: grub-common 2.04-1ubuntu26.2
Uname: Linux 5.8.0-050800-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.6
Architecture: amd64
CasperMD5CheckResult: skip
Date: Tue Aug 11 13:18:18 2020
InstallationDate: Installed on 2020-08-09 (1 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
SourcePackage: grub2
UpgradeStatus: No upgrade log present (probably fresh install)

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "Possible fix" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

[Patric (pakar)]

Patch does not work as expected.

Before the loop
            initrd_path="" <-- Needs to be cleared before the loop.
            for i in ${initrd}; do
              initrd_path="${initrd_path} ${rel_dirname}/${i}"
            done

If this is not done it will append the same data over and over to this variable creating duplicates for subsequent boot-entries..

Ie
  initrd /acpi_override /initrd.img-5.8.0 /acpi_override /initrd.img-5.8.0 /acpi_override /initrd.img-5.8.0 /acpi_override /initrd.img-5.8.0-rc7 /acpi_override /initrd.img-5.8.0-rc7 /acpi_override /initrd.img-5.4.0-42-generic /acpi_override /initrd.img-5.4.0-42-generic

[Julian Andres Klode (juliank)]

Hello Patric, I'm not sure what you're commenting on. Please recall that this is a duplicate and the patch here is not being used. If you think you found a bug in the current grub in groovy and focal-proposed, please open a new bug. Thank you!