related_name_query bug

[jerch]

Coming from #168:

There is a bug hidden in the field deps resolving for related_name_query, where an empty field list on the right side will not uncover all needed deps, while related_name does. For details see #168.

[jerch]

My suspicion goes to the auto-expansion of the resolver on deeper chains, where the attribute name automatically matches the related_name, while it cannot match the related_name_query skipping those expansions.

Since I cannot repro it atm, I gonna remove the BUG flag but keep the issue open.