etcdserver: remove TODO to delete URLStringsEqual

Discovery SRV supports to compare IP addresses with domain names,
so we need URLStringsEqual function.

etcdserver/cluster.go

@@ -421,7 +421,6 @@ func ValidateClusterAndAssignIDs(local *cluster, existing *cluster) error {
 	sort.Sort(MembersByPeerURLs(lms))
 
 	for i := range ems {
-		// TODO: Remove URLStringsEqual after improvement of using hostnames #2150 #2123
 		if !netutil.URLStringsEqual(ems[i].PeerURLs, lms[i].PeerURLs) {
 			return fmt.Errorf("unmatched member while checking PeerURLs")
 		}

etcdserver/config.go

@@ -89,7 +89,6 @@ func (c *ServerConfig) verifyLocalMember(strict bool) error {
 	}
 
 	// Advertised peer URLs must match those in the cluster peer list
-	// TODO: Remove URLStringsEqual after improvement of using hostnames #2150 #2123
 	apurls := c.PeerURLs.StringSlice()
 	sort.Strings(apurls)
 	urls.Sort()