Define OpenTracing error logging translation

[carlosalberto]

In OpenTracing there was a set of semantic conventions for logging errors, i.e.

try:
  // Failed operation
except OSError as e:
  span.log_kv({
    "event": "error",
    "error.kind": "OSError",
    "error.object": e,
    // etc
  })

We should be mapping this to the existing RecordException(e) operation (or AddEvent() with the proper semantics)

Follow up to #1101