BatteryService: don't use autoconnect with opportunistic connections

Opportunistic connections were meant to be used with autoConenct set to
false. Currently this code would keep, and create connections to
devices, which is not intended behavior - it should just use connections
when they are present.

Test: 1. connect to hid device with battery level monitor.
      2. select "disconnect in BT settings for this device.
      3. press any key, and verify device does not reconnect.
Change-Id: Ia35d830ed09c5ec8bbeb91ec97bf8abb9690b116