Fix for android build failure.

Fix for android build failure.

Background:
Recently, an API was added to retrieve the some internal values in TCP socket.
This requirement was from VD and hence it was verified on Tizen platform.
PR(merged): https://github.sec.samsung.net/RS7-IOTIVITY/IoTivity/pull/537

There is a build issue on android because <ifaddrs.h> which is used in the above patch
is not available in android-21.

Solution:
Made the corresponding API to be available only for Tizen platform.

Change-Id: Idd64911aee0f817353c3376127f53a5ac8efe650
Signed-off-by: Senthil Kumar G S <senthil.gs@samsung.com>
Signed-off-by: Sudipto <sudipto.bal@samsung.com>