Migrate can create duplicate relationships

It would appear that the buddylist module allows users to submit buddy requests to people to whom they've already submitted a request, or to people who have already submitted a request to them.

When the user_relationships_migrate plugin migrates buddylist data, and in particular when it migrates pending requests, it does not check to see if any relationships/requests already exist between the two users. This can result in multiple relationships of the same type between the same two users.

The migrate module should probably check the db prior to inserting relationships/requests to prevent duplicates.