* Path preference change was enqueued every time, interface config
  change and hence, preference would be overwritten, because of this.
  Removed the code to enqueue explicit path preference change.
  Instead copy config driven field in local vm add change path.
  Added test case for same.
Closes-bug:#1379481

Change-Id: Idb9c5eab91ed20c6119d21bae05462bc5c7744c9
Merge "* Path preference change was enqueued every time, interface config   change and hence, preference would be overwritten, because of this.   Removed the code to enqueue explicit path preference change.   Instead copy config driven field in local vm add change path.   Added test case for same. Closes-bug:#1379481" into R2.0