Sometimes Rules loses the events for the core modules

We have a module that syncs a user's profile from another server when they log in. However, after a user logs in, the Content update event stops firing.

Steps to reproduce:

1. Create a rule that act on the content updated event and displays a message.
2. Create a module with a hook_init that runs before the rules' hook_init
3. Call a function in the new hook_init that eventually calls module_implements('entity_update'). User_save does this.
4. Update a content node.
5. Observe that a message is not displayed.

What I have figured out happens is this:

1. When user_save runs. It eventualy calls module_implements('entity_update').
2. Since events.inc is not yet loaded, module_implements caches that rules does not implement hook_entity_update.
3. Later, when an entity is updated, module_implements uses the cached value and rules_entity_update is not called.

Possible Fixes:
We could move rules_init to run first with hook_module_implements_alter. We could also just include the module/events.inc file in the module.info file. We already load it in init unconditionally. I prefer the second solution as that seems more stable.