fix: server in shutdown should return 503 instead of 403 (#13496)
fix: server in shutdown should return 503 instead of 403 (#13496)

various situations where the client is retrying the request
server going through shutdown might incorrectly send 403
which is a non-retriable error, this PR allows for clients
when they retry an attempt to go to another healthy pod
or server in a distributed cluster - assuming it is a properly
load-balanced setup.
minio/minio,balamurugana/minio,donatello/minio,donatello/minio,vadmeste/minio,krisis/minio,vadmeste/minio,minio/minio,krisis/minio,balamurugana/minio