Modified getNetAddress() in SceneUtils

Modified getNetAddress() in SceneUtils

If network have IPv4 address, it returns IPv4 address.

Change-Id: Iba93339b6a980251194b02d6fa905006a88a0608
Signed-off-by: ChaJiWon <jw_wonny.cha@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/18675
Reviewed-by: Uze Choi <uzchoi@samsung.com>
Reviewed-by: JungYong KIM <jyong2.kim@samsung.com>
Tested-by: jenkins-iotivity <jenkins@iotivity.org>
(cherry picked from commit 0b1a8bce125e4543e40c4b855a64384fe7ef5865)
Reviewed-on: https://gerrit.iotivity.org/gerrit/18681
Reviewed-by: Jihun Ha <jihun.ha@samsung.com>