Handle localhost distributed setups properly (#8577)

Fixes an issue reported by @klauspost and @vadmeste

This PR also allows users to expand their clusters
from single node XL deployment to distributed mode.

pkg/net/port_test.go

@@ -49,10 +49,11 @@ func TestParsePort(t *testing.T) {
 		{"0", Port(0), false},
 		{"9000", Port(9000), false},
 		{"65535", Port(65535), false},
+		{"http", Port(80), false},
+		{"https", Port(443), false},
 		{"90000", Port(0), true},
 		{"-10", Port(0), true},
 		{"", Port(0), true},
-		{"http", Port(0), true},
 		{" 1024", Port(0), true},
 	}