kernel.spec.template: Fix --without bpftool
The selftests turn bpftool on unconditionally. If a user has specified
--without bpftool it means the user really wants to disable bpftool. In
this case the selftest should be disabled.
Disable selftests and output a message to the user disabled when --without
bpftool is specified.
Signed-off-by: Prarit Bhargava prarit@redhat.com