use plain copy instead of git-new-workdir when using --with-linked-git
configure switch (point it to your master copy of the core-repo)
also remove obsolete bin/create_bootstrap_links, bin/mkworkdir and
bin/repo-list[.in]

Change-Id: I37028badf2c46a24a3d628e80476efe4dd365d06
Reviewed-on: https://gerrit.libreoffice.org/912Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>