Fix serializer pre-commit permissions problem

[rjyounes]

Fixes #1006

[Jamie-SA]

I am not real thrilled with this change. This means that the hook will not automatically be updated when changed in the git repo.

However, there is already issue #891 about having to deal with this for the main hook, so it could be dealt with in the same way.

[rjyounes]

This means that the hook will not automatically be updated when changed in the git repo.

If the main pre-commit changes in the repo you have to rerun /tools/setup.cmd. This handles changes to the serializer pre-commit the same way, unless I'm missing something.

[Jamie-SA]

Yes, but see the issue I referenced: #891
You don't currently have to run setup.cmd if the serialize/pre-commit changes, but you will after this change.

[rjyounes]

I see. I see you added a comment to that effect on #891. It seems to me to be in principle the same issue.