Update the number of property blocks in the POIFS header block

[ebourg]

This fixes https://bz.apache.org/bugzilla/show_bug.cgi?id=66590

[centic9]

Thanks for the changes. Looks good on a brief look.

Can you add a sample .msi-file to directory test-data/poi-fs and a small unit-test which verifies opening it so we verify the intended feature as well?

[ebourg]

I did modify the existing tests to ensure the header is properly updated. I don't think adding an actual msi file will improve the test coverage, it's just a CFB file like any other one.

[pjfanning]

I don't think we should merge this without an MSI test. We have zero test coverage of MSIs.

-1 from me

[ebourg]

I can contribute one for the tests (I've built one for the Jsign tests: https://github.com/ebourg/jsign/blob/master/jsign-core/src/test/resources/minimal.msi), but a msi file is really not different from other formats handled by POIFS, and this issue is mostly related to the correctness of the header information, that's not MSI specific.