TEZ-1774. AppLaunched event for Timeline does not have start time set. (hitesh)

(cherry picked from commit f152a7f3bcca82a343b759c2921dbc8d93aaf175)

Conflicts:
	CHANGES.txt
Update CHANGES.txt for TEZ-1774. (hitesh)

(cherry picked from commit f4c2112f647ce1aa7b7ab9febad2118bd9451cc6)

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

(cherry picked from commit 1a3059f41820ce91acc9eeb3b8c30fb4b53ea2b5)
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