If a symlink, device, special-file, or hard-linked file is replacing
an existing non-directory, the new file is created using a temporary
filename and then renamed into place.  Also changed the handling of
a cluster of hard-linked symlinks/devices/special-files to always
ensure the first item in the cluster is correct, since it doesn't
really save any significant work to try to find an existing correct
item later in the cluster to link with.