common prefixes in bucket name if already created
are disallowed when etcd is configured due to the
prefix matching issue. Make sure that when we look
for bucket we are only interested in exact bucket
name not the prefix.
Currently we would end up considering common prefix
buckets to be part of the same DNS service record,
which leads to Minio server wrongly forwarding the
records to incorrect IPs.
With CoreDNS now supporting etcdv3 as the DNS backend, we
can update our federation target to etcdv3. Users will now be
able to use etcdv3 server as the federation backbone.
Minio will update bucket data to etcdv3 and CoreDNS can pick
that data up and serve it as bucket style DNS path.
