perlPackages.SysVirt: remove assert version == pkgs.libvirt.version
perlPackages.SysVirt: remove assert version == pkgs.libvirt.version

SysVirt-6.3.0 should build correctly against libvirt-6.6.0 and also
libvirt-6.7.0 since their were no API changes.

Also note that because of this there's no SysVirt-6.6.0 release.

So this removes the `assert version == pkgs.libvirt.version` protection.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs