Allow to specify alternate gtest location

Change-Id: I55bee39852b3198cd3c761ecb2f070c39853b96f
bc_http: Enhance 'always-on' mode:

- Throttle the reconnection attempt when the nodelist has been cycled
- Don't reconnect when no configuration exists (if the nodelist has
  ended)

Change-Id: Iade455ceb9ef2cc5e3c2e0e81ac99f2e6bc9d289