Merge changes from topic 'exponential backoff periodic scan' into nyc-dev

* changes:
  WifiConfigManager: clean up makeChannelList()
  WifiStateMachine: clean up dead code
  WifiConnectivityManagerTest: exponential backoff periodic scan
  Restrict connectivty periodic scan
tree: c407815478e205d0ae33f6da14b308b49134d808
  1. service/
  2. tests/