Space out first connection_edge_process_relay_cell() line in circuit_receive_relay_cell()

The first if statement containing connection_edge_process_relay_cell() looks like this

      if ((reason=connection_edge_process_relay_cell(cell, circ, conn, NULL))
          < 0) {

Whereas the second looks like this:

      if ((reason = connection_edge_process_relay_cell(cell, circ, conn,
                                                       layer_hint)) < 0) {

We should space out the first