Updated context references in yang-ext
Updated context references in yang-ext

Change-Id: Ie4675d143a739f8cb8bac3be11496737f3a97dc2
Signed-off-by: Tony Tkacik <d0658a876d3f3373fb5ecec624b553a76d54e737@cisco.com>

opendaylight/yangtools,522986491/yangtools,NovusTheory/yangtools,opendaylight/yangtools