fixed annoying log lines with buffers

These suck!

```sh
00:18:25.999Z TRACE fxa-auth-server:  (op=MySql.sessionToken)
    id: [
      174,
      183,
      42,
      152,
      7,
      214,
      190,
      88,
      219,
      126,
      67,
      187,
      7,
      201,
      51,
      119,
      200,
      5,
      236,
      191,
      207,
      219,
      171,
      159,
      160,
      171,
      175,
      170,
      190,
      72,
      230,
      165
    ]
```