Restoring deserialization compatibility broken by 6243f6b for matrix projects.
Needed to check whether projectName was in fact a real job name (MatrixRun).
Unfortunately cannot use Converter.unmarshal for this purpose:
- relative paths would not be supported, since there is no context
- unpredictable order of job load breaks logic in case copier is loaded before matrix
Instead, upgrading format if and when the project is run, when all information is available.
(Note that this means that if you open the configure page before running it after upgrade,
you will see the related fields as blank, so you would need to correct them first;
not sure if that is fixable, but this is anyway a one-time conversion.)