control: Remove JSON event precondition support

Event preconditions are essentially specialized actions that load events
after a certain condition is met. JSON configured fan control will just
utilize actions that are configured & created to enable or disable
events based on some state.

Change-Id: I8e8faf3c137062943ffaa9b3adc20d93da3a123c
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
2 files changed