Fix crash in possible error situation in _LSTransportClientNew

OWEBOS-2741
Memory was allocated with g_slice_new() and, in case of error, freed with g_free()

Open-webOS-DCO-1.0-Signed-off-by: Kari Lehikko <kari.lehikko@palm.com>

Change-Id: I7dcb625b9b0acb86d70f7b108cad54149703bc3f