BUG: Wrong FatalIOError message in displacementMethod and optMeshMovement

Summary

The core of the FatalIOError message, including the table of contents of the base class, is not printed by displacementMethod::New and optMeshMovement::New due to exiting the FatalIOError call with exit(FatalError) instead of exit(FatalIOError).

Steps to reproduce

Enter a non-valid displacementMethod (in dynamicMeshDict) or meshMovement type (in optimisationDict) in any of the tutorials under $FOAM_TUTORIALS/incompressible/adjointOptimisationFoam/shapeOptimisation.

What is the current bug behaviour?

No error message content is printed, only the Fatal Error line.

What is the expected correct behavior?

The full FatalError message, including the toc of the base class should be printed.