Neither the assignment nor the underletting of any leasehold by The Official Receiver in Bankruptcy or the trustee of the estate of a bankrupt, or by the liquidator of a company (other than a liquidator in a voluntary winding-up of a solvent company), nor the sale of any leasehold under an execution, nor the bequest of a leasehold, shall be deemed to be a breach of a covenant, condition, or agreement against the assigning, underletting, parting with the possession, or disposing of the land leased.