FIX: Query on formula m2o-property uses wrong alias:

[rPraml]

The following queries produce the wrong SQL:

    DB.find(TreeNode.class).select("id")
      .where().isNotNull("children.ref.id")
      .findList();

Actual

select distinct t0.id 
from tree_node t0 
join tree_node u1 on u1.parent_id = t0.id 
join e_basic u2 on u2.id = u1_ref.id -- unknown alias here
where u2.id is not null

Expected

select distinct t0.id
from tree_node t0
join tree_node u1 on u1.parent_id = t0.id
join e_basic u1_ref on u1_ref.id = u1.soft_ref -- this path is missing in the query above
join e_basic u2 on u2.id = u1_ref.id
where u2.id is not null