usb_device-info: Handle the case of a device being selected again.

If the user selects a device that the app has already been given permission
for then this patch moves the selection back to that device instead of adding
a duplicate entry to its internal list.
Merge pull request #333 from reillyeon/device-info

usb_device-info: Handle the case of a device being selected again.
Don't disconnect same device of GATT services
Merge pull request #334 from oahziur/ble

 bluetooth-samples_heart-rate-sensor: Don't disconnect same device of GATT services