Order all keys in config (#8541)

New changes

- return default values when sub-sys is
  not configured.
- state is hidden parameter now
- remove worm mode to be saved in config

cmd/config/cache/legacy.go

@@ -23,16 +23,36 @@ import (
 	"github.com/minio/minio/cmd/config"
 )
 
+const (
+	cacheDelimiterLegacy = ";"
+)
+
 // SetCacheConfig - One time migration code needed, for migrating from older config to new for Cache.
 func SetCacheConfig(s config.Config, cfg Config) {
 	if len(cfg.Drives) == 0 {
 		// Do not save cache if no settings available.
 		return
 	}
-	s[config.CacheSubSys][config.Default] = DefaultKVS
-	s[config.CacheSubSys][config.Default][Drives] = strings.Join(cfg.Drives, cacheDelimiter)
-	s[config.CacheSubSys][config.Default][Exclude] = strings.Join(cfg.Exclude, cacheDelimiter)
-	s[config.CacheSubSys][config.Default][Expiry] = fmt.Sprintf("%d", cfg.Expiry)
-	s[config.CacheSubSys][config.Default][Quota] = fmt.Sprintf("%d", cfg.MaxUse)
-	s[config.CacheSubSys][config.Default][config.State] = config.StateOn
+	s[config.CacheSubSys][config.Default] = config.KVS{
+		config.KV{
+			Key:   config.State,
+			Value: config.StateOn,
+		},
+		config.KV{
+			Key:   Drives,
+			Value: strings.Join(cfg.Drives, cacheDelimiter),
+		},
+		config.KV{
+			Key:   Exclude,
+			Value: strings.Join(cfg.Exclude, cacheDelimiter),
+		},
+		config.KV{
+			Key:   Expiry,
+			Value: fmt.Sprintf("%d", cfg.Expiry),
+		},
+		config.KV{
+			Key:   Quota,
+			Value: fmt.Sprintf("%d", cfg.MaxUse),
+		},
+	}
 }