brace after 'package NAME' should be an open brace, not a close brace

- `package NAME` is ok  (maybe something follows)
- `package NAME;` is ok.
- `package NAME }` is ok (same as ;, though looks weird).
- `package NAME VERSION` is ok.
- `package NAME BLOCK` is not supported now.

This fix address the last one so that it can parse `package NAME BLOCK` correctly.

cf. perldoc -f package
```
    package NAMESPACE
    package NAMESPACE VERSION
    package NAMESPACE BLOCK
    package NAMESPACE VERSION BLOCK
```