we create broken symlinks if --scandir is a relative path

[juleskers]

The test-crawl.sh script specifies ./data as scandir.
This results in relative paths being passed through the entire crawler. These are relative to the scandir, but we create the symlinks in the links subdir, without compensating for the shift, thus creating broken links.

This was masked in the production environment, because we only specify absolute paths there.

To fix: either

• document and enforce scandir to always be absolute, or
• compensate by absolute-ising the $file_to_link path just before making the symlink.