Reconcilliation in a 3 node cluster multi DPN environment

Reconcilliation in a 3 node cluster multi DPN environment

Description: In a 3 node cluster initial inventory shard status is
verified and following tests are performed

- Start Mininet 3 DPNs connect to one of the follower, add bulk 3K flows via that
  node (1K per DPN).

- Verify flows in config DS as well as in switch, Stop Mininet and
  reconnect DPNs to same follower node and verify same flows installed
  in respective DPNs.

- Stop Mininet and connect back to 2nd follower node and verify same
  flows installed in respective DPNs.

- Stop Mininet and connect back to leader node and verify same flows
  installed in respective DPNs.

- Also modified existing BulkomaticKeywords.robot library for
  implementing KWs to get json object instead of json files as argument.

- Corresponding changes are done in rest of the Clustering_Bulkomatic
  test suites.

Change-Id: Ife65746c13681377f63e152bbf88392e492924d2
Signed-off-by: Sanjib Mohapatra <sanjib.mohapatra@ericsson.com>