Make sure data defined as required generate errors if not

[hugtalbot]

Make sure the data defined as required (d_myData.setRequired(true);) generates an error if it is not indeed defined

To do so, the call to super init() must be done since this check is done in BaseObject::init()

Initiated in #2419

[hugtalbot]

a priori only MinResLinearSolver is missing it ..

[alxbilger]

a priori only MinResLinearSolver is missing it ..

MinResLinearSolver does not override init(), so I suspect its base init() is called. So no problem here. I verified by removing iterations in examples/Components/linearsolver/MinResLinearSolver.scn. It shows an error.