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
issue