Update export back-ends wrt "file" link changes
* lisp/ox-latex.el (org-latex-link):
* lisp/ox-html.el (org-html-link): Do not expand absolute file names
and do not try to fix hierarchy part, as it is already taken care of
at the parser level.
* lisp/ox-md.el (org-md-link): Ditto. Also fix absolute file names.
* lisp/ox-odt.el (org-odt-link):
* lisp/ox-man.el (org-man-link):
* lisp/ox-texinfo.el (org-texinfo-link):
* contrib/lisp/ox-groff.el (org-groff-link): Ditto. Do not prepend
scheme part to relative file names either.
* contrib/lisp/ox-deck.el (org-deck-link): Small refactoring.