We start to resolve host into tcp addrs since we generate
tcp based initial-cluster during srv discovery. However it
creates problems around tls and cluster verification. The
srv discovery only needs to use resolved the tcp addr to
find the local node. It does not have to resolve everything
and use the resolved addrs.
This fixes#2488 and #2226
Currently this doesn't work if a user wants to try out a single machine
cluster but change the name for whatever reason. This is because the
name is always "default" and the
```
./bin/etcd -name 'baz'
```
This solves our problem on CoreOS where the default is `ETCD_NAME=%m`.
etcd resolves DNS hostnames to IP addresses for client and peer URLs
before creating any listening sockets.
The following messages are logged during startup:
etcd: Resolving infra0.coreos.com:2380 to 10.0.1.10:2380
Fixes#1991
