Fix that the device is not added while detecting devices.

Fix that the device is not added while detecting devices.

- Problem: If adding a device while detecting the device, the first device
  detection callback is not called.
- Cause: If the broadcast MAC is used as a source filed in APR Request packet,
  can't distinguish ARP Response whether the device detected or the device added.
- Solution: Modified the device is not added while detecting devices.

Change-Id: I97be26be40c41a8ec4a34cfd6fc7647ab43676df
Signed-off-by: saerome.kim <saerome.kim@samsung.com>