Automatically created downtime-comments are not removed

[Corbyn]

Comments that are automatically created if a downtime is added, are not deleted after the downtime has ended, but only if Shinken is reloaded (by '/etc/init.d/shinken reload') while the downtime is active.

Steps to reproduce:

• schedule a host or service downtime
• reload shinken config while downtime is acitve
• after the downtime has ended, the automatically generated downtime-comment is still present

Tested with Shinken 2.4 and (only) scheduler retention (MongoDB or Pickle) active.

[naparuba]

Thanks I'll give a look :)