[rql2sql] fix bad sql generated when outer joining 'identity' relation and lhs var comes from a subquery. Closes #3099418
The generated SQL was attempting to access table.cw_eid which doesn't exist.
<table class="attributeForm" style="width:100%;" tal:attributes="id tab_id | nothing; class tab_class | nothing;"> <tr tal:iter="widget lines"> <th class="labelCol" tal:content="structure python:widget.render_label(entity)">attrname</th> <td tal:define="error python:widget.render_error(entity)" style="width:100%;" tal:attributes="class python:error and 'error' or nothing"> <div tal:replace="structure error">error message if any</div> <div tal:replace="structure python:widget.edit_render(entity)" >widget (input, textarea, etc.)</div> <div tal:replace="structure python:widget.render_help(entity)">format help if any</div> </td> </tr> </table>