3. Procedure where defendant is suing plaintiff.- Where any of the defendants in an interpleader suit is actually suing the plaintiff in respect of the subject matter of such suit, the court in which the suit against the plaintiff is pending shall, on being informed by the court in which the interpleader suit has been instituted, stay the proceedings as against him; and his costs in the suit so stayed may be provided for in such suit; but if, and in so far as, they are not provided for in that suit, they may be added to his costs incurred in the interpleader suit. | 