Once a FIN control message is appended to the pending list,
the ob1 PML attempts to send the FIN again in the `mca_pml_ob1_process_pending_packets` function.
But if the PML failed to sent the FIN again, the `mca_pml_ob1_send_fin`
function creates a new `mca_pml_ob1_pckt_pending_t` object and the
old object is not retured to the free list.