Scheduling of the events based on timeline is not honored
when some event is removed. This is because when we remove an
event from any position in the priority queue, we need to adjust
heap both upward and downward depending on new value at the
deleted node and the value of the parent node. If value of parent
node is less than the current value of deleted node, the heap needs
to be adjusted upwards (until heap property is satisfied) else
downwards (in comparison with it's children and exchanging if heap
property is violated). In the current code, heapify() adjusts the
heap downwards only. The update() function adjusts the heap downward
as  well as upward (based on comparison of the replaced (deleted) node
and the parent node).

Thus the patch fixes the issue by calling update() method after element
is removed, which ensures the heap property.

Change-Id: Id449f0de4c59c8f6994bcd21708d4c8038d154e4