fixing the dependency cycle that is created when using icinga::command.

Example after creating a icinga::command

```puppet
  icinga::command { 'check_https':
    command_line => '$USER1$/check_http -S -H $HOSTADDRESS$'
  }
```

```dot
digraph Resource_Cycles {
  label = "Resource Cycles"
  "File[/etc/icinga/auto.d/commands/check_https.cfg]" -> "Service[icinga]" -> "Class[Icinga]" ->
  "Icinga::Command[check_https]" -> "File[/etc/icinga/auto.d/commands/check_https.cfg]"
}
```

(File[/etc/icinga/auto.d/commands/check_https.cfg] => Service[icinga] => Class[Icinga] => Icinga::Command[check_https]
=> File[/etc/icinga/auto.d/commands/check_https.cfg])
Merge pull request #17 from Uranellus/master

fixing the dependency cycle that is created when using icinga::command.