Don't test in Go 1.4

.travis.yml

@@ -5,7 +5,6 @@ services:
   - redis-server
 
 go:
-  - 1.4.x
   - 1.7.x
   - 1.8.x
   - 1.9.x
@@ -13,7 +12,6 @@ go:
 
 matrix:
   allow_failures:
-    - go: 1.4.x
     - go: tip
 
 install:

ring.go

@@ -298,6 +298,9 @@ func (c *Ring) cmdInfo(name string) *CommandInfo {
 	if err != nil {
 		return nil
 	}
+	if c.cmdsInfo == nil {
+		return nil
+	}
 	info := c.cmdsInfo[name]
 	if info == nil {
 		internal.Logf("info for cmd=%s not found", name)