Send return value from server to client

Send return value from server to client

Current code does not send return value of server error to client which uses TIDL as IPC method.
However, this can make unintented behavior because some function like tts_play() needs to error
value for returning.

This patch makes server send return value to client although the client uses TIDL. By this change,
clients can always get proper error values from server.

Change-Id: Ibb98cd1bf64e92746022632f3bc5bf9eded904df
Signed-off-by: Suyeon Hwang <stom.hwang@samsung.com>