Also don't use storeAsURL to store embedded datasource when the document
is being saved using storeToURL.

Change-Id: I69a7ee5ae066e591be5e45c87bcf57dff370decc
Reviewed-on: https://gerrit.libreoffice.org/57178
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>