Revert "TEZ-1687. Use logIdentifier of Vertex for logging (zjffdu)"

This reverts commit 13ede7e58396c82516c99c28697e1f886507f6b4.

Conflicts:
	CHANGES.txt
Revert "TEZ-1772. Failing tests post TEZ-1737. (Jeff Zhang via hitesh)"

This reverts commit 16b21dfcb42bbb5514ef53da10563d9c7f8da283.
Revert "TEZ-1737. Should add taskNum in VertexFinishedEvent (zjffdu)"

This reverts commit 9f762dda3a81f984901de238ac830e775979095a.

Conflicts:
	CHANGES.txt