cubicweb #344484 if an error occurs during sql execution, the transaction is left in a bad state [resolved]

this wasn't occuring before thanks to systematic call to rollback in _free_pool. This has been removed in 3.3.3 because it seemed to be costly. ok, but we've now to properly rollback the transaction when an sql error occurs, else the connection is left in a bad state and reused as is, so no chance to get it working.

done in3.3.4
load left0.000
closed by<not specified>