BT: fix bluetooth process can't restart again

After enable timeout, com.android.bluetooth will be killed.
Then, com.android.bluetooth will restart.
MESSAGE_BLUETOOTH_SERVICE_CONNECTED will be sent to mHander
while recoverBluetoothServiceFromError is running.
At that time, we should not unbindService in recoverBluetoothServiceFromError.
Otherwise, after unbind, com.android.bluetooth will die, but
later mBluetooth will be assigned to adapterService in handleMessage of
MESSAGE_BLUETOOTH_SERVICE_CONNECTED. From then on, mBluetooth is not null,
but com.android.bluetooth is dead, and doBind will not be triggered again.

Change-Id: I5be867c774837be0efb504eff9352c245b432deb
CRs-Fixed: 1025113