Fixes bug 989271, fixes launched_at date on notifications.
Fixes bug 989271, fixes launched_at date on notifications.

Also adds unittests to prevent regression of bug 984219,
and adds missing backstop compute.instance.exists event.

Change-Id: I77278009962ea7f7fb940704dbb7bba637aa8e96

n0ano/gantt,n0ano/gantt