Force the use of noop ioscheduler in tutorial vagrant vms - 235

To test:

```
(235)(noop-scheduler-235 ? =)[~/.../vagrant/tutorial]$ python ./build master
```

Which will create a tutorial base image `flocker-tutorial.box` using RPMs generated by buildbot from our master branch.

You can then use that as the basis for your tutorial images by following the instructions here:
 * http://docs.clusterhq.com/en/latest/gettinginvolved/infrastructure/vagrant.html#testing


Fixes #235