Adds LOG in event_simulator.py

Reasons:
- Module method event_simulator_sleep uses LOG, but LOG was nowhere
  implemented in module.

Changes:
- Added LOG in the module.

Change-Id: I0ddee7a5d933317e3ad0add4b791e945f000629d
Closes-Bug: #1264721
Merge "Adds LOG in event_simulator.py"