Fixed missing response in TTL json command

Using the tile38-cli, the TTL command omitted the ttl value from the
json response.

For example:

    127.0.0.1:9851> TTL my ufo
    {"ok":true,"elapsed":"5.57µs"}

Is now fixed to show
    127.0.0.1:9851> TTL my ufo
    {"ok":true,"ttl":-1,"elapsed":"5.57µs"}

Where "ttl" is the remaining time before the object is is deleted.
The value -1 means that the object is available, but does not have
an expiration.

Thanks @phulst for finding this bug. closes #116

controller/controller.go

@@ -503,7 +503,7 @@ func (c *Controller) command(msg *server.Message, w io.Writer) (res string, d co
 	case "persist":
 		res, d, err = c.cmdPersist(msg)
 	case "ttl":
-		res, d, err = c.cmdTTL(msg)
+		res, err = c.cmdTTL(msg)
 	case "hooks":
 		res, err = c.cmdHooks(msg)
 	case "shutdown":

controller/crud.go

@@ -940,7 +940,7 @@ func (c *Controller) cmdPersist(msg *server.Message) (res string, d commandDetai
 	return
 }
 
-func (c *Controller) cmdTTL(msg *server.Message) (res string, d commandDetailsT, err error) {
+func (c *Controller) cmdTTL(msg *server.Message) (res string, err error) {
 	start := time.Now()
 	vs := msg.Values[1:]
 	var key, id string
@@ -976,7 +976,17 @@ func (c *Controller) cmdTTL(msg *server.Message) (res string, d commandDetailsT,
 	}
 	switch msg.OutputType {
 	case server.JSON:
-		res = `{"ok":true,"elapsed":"` + time.Now().Sub(start).String() + "\"}"
+		if ok {
+			var ttl string
+			if ok2 {
+				ttl = strconv.FormatFloat(v, 'f', -1, 64)
+			} else {
+				ttl = "-1"
+			}
+			res = `{"ok":true,"ttl":` + ttl + `,"elapsed":"` + time.Now().Sub(start).String() + "\"}"
+		} else {
+			return "", errIDNotFound
+		}
 	case server.RESP:
 		if ok {
 			if ok2 {