qemu: Remove redundant kvm group config in sysusers.d

qemu: Remove redundant kvm group config in sysusers.d

It's already defined by default in systemd:
https://github.com/systemd/systemd/blob/v257.6/sysusers.d/basic.conf.in#L32

Adding it again here in libvirt-qemu.sysusers.conf causes the following
warning by validating it with sd-sysuers:

	/usr/lib/sysusers.d/libvirt-qemu.conf:1: Conflict with earlier configuration for group 'kvm' in /usr/lib/sysusers.d/basic.conf:32, ignoring line.

On Fedora/RHEL systemd is built with -Dkvm-gid=36 so there is no change
in the allocated GID on these platforms. Other platforms have the same
facility available to them if they wish to retain a fixed GID.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Achill Gilgenast <achill@achill.org>