added pw to signal

[jrmlhermitte]

Our redis is password protected. This is just a suggestion. Should we allow for passing passwords to signal?

My lightflow.cfg file now has something like:

celery:
redis://:xxxxx@cmb03.cs.nsls2.local:6379/0
  broker_url: redis://:xxxxx@cmb03:6379/0
  result_backend: redis://:xxxxx@cmb03:6379/0
  worker_concurrency: 8
  result_expires: 0
  worker_send_task_events: True
  worker_prefetch_multiplier: 1
signal:
  host: cmb03
  port: 6379
  password: xxxxx
  database: 0
  polling_time: 0.5 

[jrmlhermitte]

Also, when moving to a password protected mongo, we might need the same flexibility. Need option to default password to None in this branch.

[jrmlhermitte]

thanks!