python-jsonschema dependency against a version

[Javier Collado]

The pyhon-jsonschema dependency doesn't work fine in quantal, because when there's a problem during the VM provisioning and the tester tries to manually fix it, it might end up with the version 0.2 instead of 0.5 if the PPA wasn't correctly added to sources.

After that, the main symptom of the problem is that the validation of the runlist fails which is misleading if the tester isn't aware that the old version of python-jsonschema fails to validate the schemas we're currently using.

To fix this, the version number should be added to the packaging dependency.

[Martin Pitt (pitti)]

I. e. please update the dependency to be (>= 0.5~). Thanks!