Use FSResolveAliasFile at least on OS X < 10.6

(see also: commit 7aa42913bb1828b877c2f73b4fe59cc3c65a67bf)

Change-Id: I6b8945bfcfce277eefdd54d25c7827c2ae19ef16
Reviewed-on: https://gerrit.libreoffice.org/8394
Reviewed-by: Norbert Thiebaud <nthiebaud@gmail.com>
Tested-by: Norbert Thiebaud <nthiebaud@gmail.com>