Turns out that SfxObjectShell::CreateShellID() will produce the
SfxMedium's base URL if it exists, so
EmbeddedObjectContainer::CopyAndGetEmbeddedObject() already has
parameters, sw just needs to set them.

Change-Id: I36cedfde4e7c2e25c43c66a30d8ca572f099ad69
(cherry picked from commit e4a06fc9)