Cleanup: Controller program return codes should be more generalized.

Cleanup: Controller program return codes should be more generalized.

It turns out that when agetty returns on access denied while trying to login, it returns access denied to the controller program.
The controller program has no way of distinguishing that this is access denied while trying execute the program to this is access denied because the program returned access denied.
Change the error messages to be more generalized so that they are less misleading.