Do not try to use INetURLObject class for encoding of internal document links.
External URLs are encoded as before.

Change-Id: I90621819ed21c3f793171ac4ab3fc7d49ac69f56
Reviewed-on: https://gerrit.libreoffice.org/15625Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>