rpc/bt: fix bt socket read

  * Fix BT socket read() to read until the specified number of bytes are
    read or fails.

  * Change GattReader to use AUTO for all device type since it doesn't
    seem to help.

MultiPart: 1/2

Change-Id: I31c4ba5566c10f8f0fda6f0e92261231b028468f
3 files changed