Fix IidCodec broken by new yangtools

Fix IidCodec broken by new yangtools

There are multiple versions of network-topology loaded
and yangtools can't tell which one to use. It has ramifications
beyond just OVSDB, but this fixes functionality issues in
OVSDB.

Root issue is two different files with different versions
bundled together. It may not have been issue earlier but is now.

Change-Id: Ibc7f8387c5b84cb6e1c0e8a69454acb661a4acc4
Signed-off-by: Vishal Thapar <vishal.thapar@ericsson.com>
Signed-off-by: Stephen Kitt <skitt@redhat.com>