Return local shard tree from FindPrimaryShard

Return local shard tree from FindPrimaryShard

Added a new ShardLeaderStateChanged message that includes the Shard's
DataTree as an Optional. If the shard is the leader, it returns it's
local DataTree, oherwise returns absent.

The ShardManager now returns a LocalPrimaryShardFound response to
FindPrimary if the shard's DataTree is present. Otherwise it returns
RemotePrimaryShardFound (renamed from PrimaryFound).

Change-Id: I4413aacfff3d3d2ee89df7c4a3a1d7f7c3d2c486
Signed-off-by: Tom Pantelis <tpanteli@brocade.com>
(cherry picked from commit fdddb482b07c3ee2f3ca853d09ee9a6ecdd7eb2a)