clarify startup config output

[roadscape]

Glancing at startup logs, it would appear the runmode is sync, when it's actually server (Command Line Args override Defaulys.mode but the output is not clear).

INFO:root:loaded configuration:
Command Line Args:   server
Environment Variables:
  DATABASE_URL:      postgresql://...
  STEEMD_URL:        https://...
  HTTP_SERVER_PORT:  8080
  LOG_LEVEL:         INFO
Defaults:
  mode:              ['sync']
  --max-workers:     4
  --max-batch:       50
  --trail-blocks:    2
  --sync-to-s3:      False
  --test-disable-sync:False
  --test-profile:    False