Regression from 2157a353

  sfx2 store: try rename before copying

  Rename is cheaper then copying the content over manually, so try that
  first.

On Windows, we need to keep the file's dentity, including metadata (e.g.,
creation time, which is kept in FS). WinAPI has ReplaceFileW specifically
for this, and it keeps ACLs of the original file, and otherwise makes the
changed file not a separate entry, but updated old file from system's PoV.

Eventually, we could try to restructure creating backup copies (e.g., for
documents when configured so) to take advantage of this function being able
to do that.

Change-Id: I6001a2a3af5e10bc010f5ef129f4bb6f83ee1581
Reviewed-on: https://gerrit.libreoffice.org/60163Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
Tested-by: Jenkins