Make git archive respect core.autocrlf when creating zip format archives
There is currently no call to git_config at the start of cmd_archive.
When creating tar archives the core config is read as a side-effect of
reading the tar specific config, but this doesn't happen for zip
archives.
The consequence is that in a configuration with core.autocrlf set,
although files in a tar archive are created with crlf line endings,
files in a zip archive retain unix line endings.