Fixes #2159 - problem with command builder for delete with joins.
Merge pull request #2160 branch '2159-fix-delete-with-join' of https://github.com/serebrov/yii into serebrov-2159-fix-delete-with-join

* '2159-fix-delete-with-join' of https://github.com/serebrov/yii:
  Fixes #2159 - problem with command builder for delete with joins.

Conflicts:
	CHANGELOG
some adjustments to pull request #2159