fixed updateCall cannot response 202 Accepted (#451)

lib/routes/api/accounts.js

@@ -1065,8 +1065,15 @@ const updateCall = async(req, res) => {
         logger.error(`Error sending updateCall POST to ${url}`);
         return res.sendStatus(500);
       }
-      const body = await response.json();
-      return res.status(200).json(body);
+      if (response.status === 200) {
+        // feature server return json for sip_request command
+        // with 200 OK
+        const body = await response.json();
+        return res.status(200).json(body);
+      } else {
+        // rest commander returns 202 Accepted for all other commands
+        return res.sendStatus(response.status);
+      }
     }
     else {
       logger.debug(`updateCall: call not found for call sid ${callSid}`);