Rudder

We have an assert in Certificate and PublicKey object in webapp/sources/ldap-inventory/inventory-api/src/main/scala/com/normation/inventory/domain/DataTypes.scala.

When, for some unknown reason, that data is empty, it kills rudder (see #20338). This is not what should be done. We should take care of the fact, and return an error to the caller.

I'm not sure how the bad data reached that point, but it should not be handled like that. On the other hand, the guard worked as expected, and the error was spotted quickly.
(I suspect that a node info cache update was triggered in the middle of the node creation, and so the certificate data were not present, but not sure).

I propose to change only in 7.0.