store: remove unused code

store/ttl.go

@@ -1,20 +0,0 @@
-package store
-
-import (
-	"strconv"
-	"time"
-)
-
-// Convert string duration to time format
-func TTL(duration string) (time.Time, error) {
-	if duration != "" {
-		duration, err := strconv.Atoi(duration)
-		if err != nil {
-			return Permanent, err
-		}
-		return time.Now().Add(time.Second * (time.Duration)(duration)), nil
-
-	} else {
-		return Permanent, nil
-	}
-}