Fix issues with LeastLoadedCandidateSelectionStrategy

Fix issues with LeastLoadedCandidateSelectionStrategy

LLCSS degenerates into a round robin owner allocator when
ownership changes. This patch fixes that issue as follows,

- Consider the statistics that are collected using the DTL
  only as initialStatistics which are passed to the Strategy
  when it is created
- When Leadership changes clear all the strategies so that
  they get freshly created with the right initial statistic
- Modify the newOwner method on Strategy to
    - pass the currentOwner for the entity, for the current
      owner we decrease the ownership statistic
    - remove the statistics passed to it as it would no longer
      be required. Due to this removal we also get rid of all
      the CRUD which we had added to check if the passed in
      stats were actually greater than the local stats which
      anyway did not work.

Change-Id: I754f0459051687a95056857044777ca6eebbcd93
Signed-off-by: Moiz Raja <moraja@cisco.com>