In ActiveRecord::Inheritance.compute_type, only swallow the NameErrors
arising directly from the failed lookup attempts.

This fix prevents us from improperly swallowing errors when the module
being looked up exists but includes an bad reference in its
definition. In those cases it is better to fail noisily with the
actual bad reference, than to silently swallow the error.

This swallows errors only the #missing_name is the candidate or the
candidate's parent.