unserialize_config: section read as keyval

[hoffa2]

What should be the behavior of dc_finalize on a keyval when its mold equivalent is of type section
and dc_fatal_error is called with context (context keyval is in fatal state).
Came across this when testing unserialize_config, and as of now finalize returns
context in wrong state, which is expected. However, in order to recover and present such an
error wouldn't it be better if a context of wrong type whose root context is of type config is allowed to
be finalized. That is, with a name and the error INVALID_CONTEXT is return from dc_finalize?

[veeg]

This problem is currently limited by a design flaw that does not allow an element to receive operations designed for the other element type. Therefore, we are not able to reliably fix this issue in the current implementation.