package/e2fsprogs: explicitly do not install udev and systemd files for host variant

package/e2fsprogs: explicitly do not install udev and systemd files for host variant

Explicitly do not install udev rules and systemd units when installing
the host version of e2fsprogs, as we do not need those files when
calling host tools provided by e2fsprogs from Buildroot.

This fixes a weird issue I encountered: host-e2fsprogs was built and
installed without any issue when building an image from scratch. But
any attempt to rebuild host-e2fsprogs alone was failing during the
installation steps as it tried to install files to the host system.

This is because e2fsprogs' build system (autotools) is using the
prefix given at configuration time when installing its binaries,
configuration files, man pages, etc... but not when installing its
systemd units and udev rules.

The issue did not arise when building it from scratch, as
host-e2fsprogs do not have a dependency on host-udev/systemd, so its
configure script did not automatically enable udev/systemd
installation steps at first.

Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>