Impacted versions:
9.0, 10.0, 11.0 (Maybe 8.0)
I don't know if it is really an expected behaviour for odoo but I like to expose it

Steps to reproduce:

1. Open an ir.cron record and change it to:
 - interval: minutes
 - next execution date: now + 1 minute

2. Open the odoo server log

Note: I'm using workers=3 but I don't know if there is possible to reproduce it without workers.

Current behavior:

You will see for each cron execution the following output
```txt
...
2018-06-01 16:18:33,432 20686 INFO 333561-11-0-42aff9-all odoo.modules.registry: Invalidating all model caches after database signaling.
...
2018-06-01 16:17:21,527 20687 INFO 333561-11-0-42aff9-all odoo.modules.loading: loading 1 modules...
2018-06-01 16:17:21,535 20687 INFO 333561-11-0-42aff9-all odoo.modules.loading: 1 modules loaded in 0.01s, 0 queries
2018-06-01 16:17:21,594 20687 INFO 333561-11-0-42aff9-all odoo.modules.loading: loading 206 modules...
2018-06-01 16:17:21,718 20687 INFO 333561-11-0-42aff9-all odoo.modules.loading: 206 modules loaded in 0.12s, 0 queries
2018-06-01 16:17:21,989 20687 INFO 333561-11-0-42aff9-all odoo.modules.loading: Modules loaded.
```

Expected behavior:
 - Review if the method that run from the cron really requires a invalidate cache and delete all registries.
 - Disable "minutes" for cron interval because all cache are deleted then is not valid use them.

Video/Screenshot link (optional):

 - [![IMAGE ALT TEXT HERE](https://img.youtube.com/vi/Be4FIeQjgjk/0.jpg)](https://youtu.be/Be4FIeQjgjk)
pass
    def run(self):
        try:
            self.start()
            while self.alive:
                self.process_limit()
                self.multi.pipe_ping(self.watchdog_pipe)
                self.sleep()
                self.process_work()
            _logger.info("Worker (%s) exiting. request_count: %s, registry count: %s.",
                         self.pid, self.request_count,
                         len(openerp.modules.registry.RegistryManager.registries))
            self.stop()
        except Exception:
            _logger.exception("Worker (%s) Exception occured, exiting..." % self.pid)
            
            sys.exit(1)
class WorkerHTTP(Worker):