validate -v cannot be used without commit-id

running `./.git/hooks/validate.sh -v ` gives me

```
Assertion failed: Precondition: hash -v must have length 64.
Backtrace:
  [1]: ./.git/hooks/timestamping : extract_token_from_commit line 200
  [2]: ./.git/hooks/validate.sh : validate_commit line 97
  [3]: ./.git/hooks/validate.sh : validate_commit_and_parents line 300
  [4]: ./.git/hooks/validate.sh : main line 329
```