Various package managers are pulled in as dependencies of core
system software (dpkg by dash on Debian, rpm by kmod via
suse-module-tools on opensuse) so let's default to always cleaning
package manager metadata even if the package manager is installed.
We still allow disabling it as having the package manager metadata
available is useful when debugging dependencies and why specific
packages are installed in the initrd.
[Content]
Bootable=no
MakeInitrd=yes
+@CleanPackageMetadata=yes
Packages=
systemd # sine qua non
udev