Some metrics aren't output after upgrated from 2.13 to 2.14

upstream_status and upstream_response_time_seconds aren't output after upgrated from 2.13 to 2.14.
These parameters are output when I install 2.14 directly.

How to reproduce:

1. Install 3scale 2.13.
2. Promote the default API to production.
3. Call the API a few times.
4. $ oc rsh <apicast-production pod> curl localhost:9421/metrics
5. Confirm upstream_status and upstream_response_time_seconds are output
6. Update to 2.14
7. Call the API a few times.
8. $ oc rsh <apicast-production pod> curl localhost:9421/metrics
9. Confirm upstream_status and upstream_response_time_seconds aren't output. They should be output.
10. Install 3scale 2.14 from scratch to another project.
11. Promote the default API to production.
12. Call the API a few times.
13. $ oc rsh <apicast-production pod> curl localhost:9421/metrics
14. Confirm upstream_status and upstream_response_time_seconds are output