DruidLeaderSelector interface for leader election and Curator based impl.#4699

Merged

drcrallen merged 9 commits intoapache:masterfrom

himanshug:membership_pr2_1

Sep 1, 2017

Commits on Aug 22, 2017

DruidLeaderSelector interface for leader election and Curator based impl. DruidCoordinator/TaskMaster are updated to use the new interface.
himanshug
committed
add fake DruidNode binding in integration-tests module
himanshug
committed

Commits on Aug 24, 2017

add docs on DruidLeaderSelector interface
himanshug
committed

Commits on Aug 28, 2017

remove start/stop and keep register/unregister Listener in DruidLeaderSelector interface
himanshug
committed

Commits on Aug 30, 2017

Commits on Sep 1, 2017