Rename (with a silent compat shim) couple of badly named customcond args

Rename (with a silent compat shim) couple of badly named customcond args

foreign_relname makes absolutely no sense - it *is* a relationship after all,
of course it has a name. Now renamed to rel_name to be consistent with
the relationship condition resolver

self_rowobj uses the old rowobj nomenclature - switch to self_resultobj