Remove old exclude files before copying new ones

Old exclude files are not being removed before new ones are copied, which can cause obsolete files to persist.

The `jckupdater.sh` script should delete old `.jtx` and `.kfl` files, if exist, from the git repo before copying the new ones.

Start with the jckupdater.sh script and trace the step that copies the new exclude files into the git repo. Ensure old .jtx and .kfl files are removed before copying, then verify that obsolete files no longer persist after an update.

Written by the indexing model from the issue text.