bug fixed (group_invite sample app for D2S communication)
bug fixed (group_invite sample app for D2S communication)

Change-Id: I4e578e75cc33649fefdaa440f660c06fc12ead4a
Signed-off-by: yeonghun.nam <c9b04b5638b760740d5ea8407d1c01f4da969b1e@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/19697
Tested-by: jenkins-iotivity <d95b56ce41a2e1ac4cecdd398defd7414407cc08@iotivity.org>
Reviewed-by: jung seungho <0a8508d3111b8c2700a5278b178871fb8ca07ad5@samsung.com>
Reviewed-by: Jee Hyeok Kim <ecfb86b5d85d5430a7602d1e11f4f25d16714d36@samsung.com>

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