cubicweb #1373227 pb in c-c list version configuration pb detection [resolved]

for instance, with an 'intranet' instance but not book cube available, is have the following message :

Errors:
* cube book is not installed, but required by None

I had a look, the pb is in consistency check of ConfigurationProblem.solve, and there seems to have something wrong in there that needs a deeper look...