spec: Use --enable-werror on RHEL
spec: Use --enable-werror on RHEL

As RHEL provides a stable tool chain, we don't have to worry about
frequent changes in reported compiler warnings (which prevents us from
enabling -Werror unconditionally).

nertpinx/libvirt,agx/libvirt,taget/libvirt,crobinso/libvirt,jardasgit/libvirt,elmarco/libvirt,fabianfreyer/libvirt,libvirt/libvirt,elmarco/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,cbosdo/libvirt,olafhering/libvirt,olafhering/libvirt,cbosdo/libvirt,crobinso/libvirt,rlaager/libvirt,fabianfreyer/libvirt,libvirt/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,taget/libvirt,zhlcindy/libvirt-1.1.4-maintain,jfehlig/libvirt,shugaoye/libvirt,andreabolognani/libvirt,agx/libvirt,shugaoye/libvirt,datto/libvirt,agx/libvirt,taget/libvirt,olafhering/libvirt,eskultety/libvirt,jfehlig/libvirt,libvirt/libvirt,eskultety/libvirt,jfehlig/libvirt,datto/libvirt,elmarco/libvirt,libvirt/libvirt,taget/libvirt,nertpinx/libvirt,shugaoye/libvirt,andreabolognani/libvirt,eskultety/libvirt,jardasgit/libvirt,zippy2/libvirt,zippy2/libvirt,eskultety/libvirt,shugaoye/libvirt,nertpinx/libvirt,jardasgit/libvirt,VenkatDatta/libvirt,zhlcindy/libvirt-1.1.4-maintain,olafhering/libvirt,shugaoye/libvirt,andreabolognani/libvirt,rlaager/libvirt,rlaager/libvirt,VenkatDatta/libvirt,zhlcindy/libvirt-1.1.4-maintain,nertpinx/libvirt,VenkatDatta/libvirt,zippy2/libvirt,cbosdo/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,crobinso/libvirt,datto/libvirt,VenkatDatta/libvirt,taget/libvirt,agx/libvirt,jardasgit/libvirt,crobinso/libvirt,eskultety/libvirt,datto/libvirt,elmarco/libvirt,zippy2/libvirt,jfehlig/libvirt,cbosdo/libvirt,agx/libvirt,rlaager/libvirt,VenkatDatta/libvirt,zhlcindy/libvirt-1.1.4-maintain,rlaager/libvirt,zhlcindy/libvirt-1.1.4-maintain,cbosdo/libvirt,datto/libvirt,elmarco/libvirt,andreabolognani/libvirt