spec: Fix 'libvirt-daemon-driver-storage-zfs' on Fedora 43 and newer

spec: Fix 'libvirt-daemon-driver-storage-zfs' on Fedora 43 and newer

On Fedora 43 and newer the 'fuse-zfs' package was removed. Commit
bd30147e740 added an 'Obsoletes' directive so that the storage driver
core package will update properly but hardcoded the obsoleted version
as 11.4 (when the change was comitted) similarly to the old sheepdog/rbd
packages and disabled the build.

Now it is still possible to obtain ZFS support from other means and it
may be useful for users to have libvirt's ZFS backend. This patch thus:

 - re-enables build of 'libvirt-daemon-driver-storage-zfs' on Fedora
 - removes 'libvirt-daemon-driver-storage-zfs' as 'Requires dependency
   from 'daemon-driver-storage' meta-package on Fedora 43 and newer
 - removes dependancy on '/sbin/zpool' and '/sbin/zfs' on Fedora 43
   and newer

With this the package still is built and installable but will require
users to get their ZFS support installed somehow.

Fixes: bd30147e740d49fdb5844160e480ca34611f75e5
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>