Missing svn r532 ("introduce explicit zzip_maphandle_t to allow default_io to be readonly")

[jwilk]

The last commit from the old Subversion repository (r532, "introduce explicit zzip_maphandle_t to allow default_io to be readonly") is not included in this git repo.
(I don't have any personal interest in this commit, so if the omission was intentional, that'd be fine with me. I just thought it's weird this one commit is missing.)