We were not properly freeing the port privates.
In order to access those at CloseScreen time, don't free the adaptor pointers
at XV screen init, but hold on to them until CloseScreen.

Also properly free the new_adaptors pointer.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>