ElanInstance DS not populated properly

ElanInstance DS not populated properly

While debugging "VMs cannot refresh IPs via DHCP",
it was seen that in "updateOperationalDataStore" method,
we were not writing to ElanInstance DS properly, due to
which, ElanInstance DS was having certain fields null and
eventually not programming table 36 and table 52 (for remote
unknown DMAC flow).

Now, fixing this issue to populate ElanInstance DS properly.

Change-Id: If2132ae191b5694074a272fc4baf37757da6f88c
Signed-off-by: Amitesh Soni <amitesh.soni@ericsson.com>