Remove all signals when an event is removed

Each event could have multiple signals associated and when the event is
removed, all of those signals should also be removed. This ensures no
dangling signals remain after an event is removed from be processed by
fan control

Tested:
    The total number of signals subscribed are reduced by the same
number of signals of a removed event

Change-Id: I651f70dbe6aed9c7eef06aff4eac9eae7ad89d77
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
2 files changed