minizip: close filestream on error in zipOpen3()

[a-kulakov]

As on error with zi ALLOC, ZCLOSE64() should match ZOPEN64() at the beginning of the function.

[praiskup]

Minizip contrib module is not maintained here. See #229, #211, #210, #209. Take a look at https://github.com/nmoinvaz/minizip

[a-kulakov]

@praiskup - Pavel, thanks. Your comments in #229 was especially helpful. And silence in reply :-)
Helped me to understand that I should close this pull request.

@madler - "zlib on github" link on http://zlib.net or zlib Faq may be a proper place to point out that pull requests with changes in ./contrib should not be created, etc. Please consider to put clear statement somewhere.

[a-kulakov]

Well, learned that "UNSUPPORTED" in README.contrib also means that pull requests just ignored :-)