Request body not sent to redirected server when redirect following is enabled

[mbrkic4]

When redirect following is enabled for the Netty client, Spring Cloud Gateway doesn't send POST body to redirected location.

Minimal demo of the problem using Spring Cloud Hoxton.SR8 can be found here:
spring-cloud-gateway-demo-master.zip

[spencergibb]

We don't currently support this. Marking as waiting for votes to see if others might want this.