We used to prevent sample hook scripts shipped in templates/ from
triggering by default by relying on the fact that we install them as
unexecutable, but on some filesystems, this approach does not work.
They are now shipped with ".sample" suffix.  If you want to activate
any of these samples as-is, rename them to drop the ".sample" suffix,
instead of running "chmod +x" on them.  For example, you can rename
hooks/post-update.sample to hooks/post-update to enable the sample
hook that runs update-server-info, in order to make repositories
friendly to dumb protocols (i.e. HTTP).