Routing policy fails when a request doesn't match any mapping rules

Issue

• Routing policy fails when a request doesn't match any mapping rules
  1) Create a product, an application plan, and an application
  2) Confirm a GET request to the product and get a 200 OK response.
  3) Add Routing policy to the product. Configure operations like this:

  "condition": {
      "combine_op": "or",
      "operations": [
          {
              "value_type": "plain",
              "op": "==",
              "value": "/aaa",
              "match": "path",
              "header_name": "dummy-header"
          }
      ]
  },
  "url": "https://echo-api.3scale.net"
  

  4) Confirm a GET request that the path is /aaa is routed by the policy
  5) Confirm a POST request that the path is /aaa gets 404 No Mapping Rule matched.
  6) Add a mapping rule POST /
  7) Confirm a POST request that the path is /aaa is routed by the policy