LJ::clear_rel — Deletes a relationship between two users or all relationships of a particular type for one user, on either side of the relationship. One of userid,targetid -- bit not both -- may be '*'. In that case, if, say, userid is '*', then all relationship edges with target equal to targetid and of the specified type are deleted. If both userid and targetid are numbers, just one edge is deleted.
LJ::clear_rel(dbs, userid, targetid, type);
1 if clear succeeded, otherwise undef