spec: Remove Group: tags
spec: Remove Group: tags

It's only required on el5 which we don't support anymore. Everywhere
else it's not used for anything useful

https://fedoraproject.org/wiki/RPMGroups

Signed-off-by: Cole Robinson <7cd45ff6ad1fb7cf556a02797d774247851499f8@redhat.com>

andreabolognani/libvirt,crobinso/libvirt,nertpinx/libvirt,libvirt/libvirt,crobinso/libvirt,crobinso/libvirt,nertpinx/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,libvirt/libvirt,eskultety/libvirt,fabianfreyer/libvirt,eskultety/libvirt,nertpinx/libvirt,zippy2/libvirt,zippy2/libvirt,jfehlig/libvirt,jfehlig/libvirt,andreabolognani/libvirt,crobinso/libvirt,zippy2/libvirt,olafhering/libvirt,olafhering/libvirt,jardasgit/libvirt,eskultety/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,nertpinx/libvirt,eskultety/libvirt,jardasgit/libvirt,nertpinx/libvirt,zippy2/libvirt,jfehlig/libvirt,libvirt/libvirt,olafhering/libvirt,andreabolognani/libvirt,libvirt/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,olafhering/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,eskultety/libvirt,jardasgit/libvirt