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. In the current code,
_downheap() adjusts the heap downwards. The queue_fix() function adjusts
the heap at every location by calling _downheap and this ensures the heap
property is satisfied if we call queue_fix() method after removing the
element from an interior node in the heap.
The patch fixes the problem mentioned by ensuring after an event is removed
from the queue at any index other than 0(top element), we call queue_fix()
function. This ensures the heap property is maintained.

Change-Id: I83c6c593f92ad9e126d846b400fb9f85f65e2273