The hard-coded "/" separator causes getFileURLFromSystemPath to fail,
and it's not obvious why the URL is being converted to a system path
in the first place.

Change-Id: I06ebe6d92954c4f3c884ae6f0b327ea8a36c10a4
(cherry picked from commit 8bf374b9)
Reviewed-on: https://gerrit.libreoffice.org/17512Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>