Adds test suits for Cluster HA Leader follower failover

Adds test suits for Cluster HA Leader follower failover

Description: Flow add modify and delete at leader or follower also test same
after leader follower or cluster restart

Initial inventory shard status test among cluster nodes. Switch connected to
leader or follower node and verify flow  add, modify, delete in leader or
follower nodes. Similarly verify RPC flow add, modify, delete in leader as
well as follower nodes. Reiterate the same functional test after leader
restart, follower restart and cluster restart.

Following changes are incorporated.

- Wrote good and meaningfull commit message

- Removed "Kill Specific Controller" and "Start Specific Controller" instead
  used alredy existing "Kill One or More Controllers" and "Start One Or More
  Controllers" in ClusterKeywords

- Used tidy tools for the checked in files

- Revert back the timer to original 15secs  in ClusterOpenFlow
  for flow add modify

- Removed ${KARAF_HOME} ${WORKSPACE}/${BUNDLEFOLDER} from test suite file

- Modified keyword "Start Multiple Controllers" so that first all nodes
  restarts and then "Wait For Controller Sync" performed in all controller
  nodes

Change-Id: I62d9f6c487d591b21b1fccdda9a5618ed3df5295
Signed-off-by: Sanjib Mohapatra <sanjib.mohapatra@ericsson.com>