fix for Leshan: n field in json can be optional now

Signed-off-by: eantwuh antal.wu-hen-chang@ericsson.com

src/EPTF_LwM2M_LGen_Functions.ttcn

@@ -1556,6 +1556,8 @@ module EPTF_LwM2M_LGen_Functions
               { v_res.val := v_LwM2M_msgToProcess.pdu.Write.resources[0].val; vl_typeMatched := true; }
               else if (ischosen(v_res.val.opaqueValue) and ispresent(v_LwM2M_msgToProcess.pdu.Write.resources[0].val.opaqueValue))
               { v_res.val := v_LwM2M_msgToProcess.pdu.Write.resources[0].val; vl_typeMatched := true; }
+	      else if (ischosen(v_res.val.opaqueValue) and ispresent(v_LwM2M_msgToProcess.pdu.Write.resources[0].val.strValue))
+              { v_res.val.opaqueValue := char2oct(v_LwM2M_msgToProcess.pdu.Write.resources[0].val.strValue); vl_typeMatched := true; }
 
               if (vl_typeMatched)
               {