VT: ARTPConnection: Supports ipv6

ARTPConnection should sent/receive packets even in IPv6 network.
This is common scenario for IMS video calling.

Merged-in: Ia1c02a9143d4e913395a2cd05386fb7d026ba821
Change-Id: Ia1c02a9143d4e913395a2cd05386fb7d026ba821
Signed-off-by: Byeongjo Park <bjo.park@samsung.com>