Previously (since commit 7eb5e135)
only path relative to reference host was stored, and host itself
was dropped. That resulted in URIs like "/share/file.xlsx", even
without scheme. For Windows shares, this broke UNC paths like
"\\HOSTNAME\share\file.xlsx" (which are stored in XLSX by Excel as
"file:///\\HOSTNAME\share\file.xlsx"), and on subsequent import,
this resulted in paths on the same drive as the document (like
"C:\share\file.xlsx").

With this change, we will store "file://HOSTNAME/share/file.xlsx",
which is correctly processed by both LibreOffice and MS Excel.

Change-Id: I3f13aa0b3ae8dc41ec28eaa1416d536469c4562a
Reviewed-on: https://gerrit.libreoffice.org/59064Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>
Tested-by: Mike Kaganski <mike.kaganski@collabora.com>