Let checks.c handle check scheduling intitalization

Since the modules should know about themself, and not depend on other
parts to initialize it's events, the check execution initialization
should be handled in the check exeuction module, not in the event
scheduling module.

It lead to really nasty dependencies, and still does, but not as much.

Signed-off-by: Max Sikstrom <msikstrom@op5.com>