JAV-492 edge service not properly handle 404 requests

[weichao666]

1. start edge service;
2. start a servicecomb provider
   request http://127.0.0.1:9990/test(provider directly) given 404 and Not Found mesage
   request edge: http://127.0.0.1:18080/api/travel-service/test give 500 Internal Server Error

[coveralls]

Coverage decreased (-0.005%) to 86.441% when pulling 053ea74 on wWX495170:master into 9f0e2fa on ServiceComb:master.

[wujimin]

UT?