Enable the service by default on Debian

In order to run the sysstat at system start and enabling the collection of performance data you need to change the ```ENABLED``` parameter to ```true``` in ```/etc/default/sysstat```

This can be simply done with augeas:
```augeas { '/etc/default/sysstat':
    context => '/files/etc/default/sysstat/',
    changes => 'set ENABLED true',
    require => Package['sysstat'],
  }```
Merge branch 'b13n1u-patch-1'
remove rspec usage of include_class

    DEPRECATION: include_class is deprecated. Use contain_class instead.
add rspec coverage of service enable on Debian