update rbh-config reset_classes for v3

[dnhodgson]

When running rbh-config reset_classes against version 3 of robinhood it doesn't clear the classes correctly.

Looking through the code it's trying to null arch_cl_update and rel_cl_update but those columns don't exist. I manually ran the following to null the classes in our test environment and it seems to have worked.

update ENTRIES SET fileclass=NULL,class_update=NULL;