in cluster calls, set user agent

[Dieterbe]

before

POST /index/find HTTP/1.1.
Host: 10.36.10.50:6060.
User-Agent: Go-http-client/1.1.
Content-Length: 58.
Content-Type: application/json.
Uber-Trace-Id: 1d0fc4fe63bc4740:711fa951aa00a28b:188525e7ddc4c59b:0.
Accept-Encoding: gzip.
.
{"patterns":["some.id.of.a.metric.1*"],"orgId":1,"from":0}

after

POST /index/find HTTP/1.1.
Host: 172.23.0.15:6060.
User-Agent: metrictank/v0.13.0-7-g267c5bb (mode Shard; state NodeReady) Go/go1.13.
Content-Length: 58.
Content-Type: application/json.
Uber-Trace-Id: 5ef53711c1016414:3c63b8cea9962f65:1353d9db56dae1b7:1.
Accept-Encoding: gzip.
.
{"patterns":["some.id.of.a.metric.1*"],"orgId":1,"from":0}

[woodsaj]

why?

[Dieterbe]

it's helpful when troubleshooting by ngrepping or tcpdumping