service-proxy: emit recvd stat if rejecting frame

[Raynos]

We had a bug where customers saw more errors then recvd.

This is because the recvd stat is emitted by either:

• RelayHandler
• EndpointHandler

When we reject a request due to rate limiter or circuit breaker we increment latency & error but do not increment recvd

r: @jcorbin @rf @kriskowal

[rf]

cool. :+1: once travis