Ignore windows hidden folders (#6735)

On Windows erasure coding setup if

```
~ minio server V:\ W:\ X:\ Z:\
```

is not possible due to NTFS creating couple of
hidden folders, this PR allows minio to use
the entire drive.

cmd/format-xl.go

@@ -379,6 +379,22 @@ func saveFormatXL(disk StorageAPI, format interface{}) error {
 	return disk.RenameFile(minioMetaBucket, formatConfigFileTmp, minioMetaBucket, formatConfigFile)
 }
 
+var ignoredHiddenDirectories = []string{
+	minioMetaBucket,
+	"lost+found",
+	"$RECYCLE.BIN",
+	"System Volume Information",
+}
+
+func isIgnoreHiddenDirectories(dir string) bool {
+	for _, ignDir := range ignoredHiddenDirectories {
+		if dir == ignDir {
+			return true
+		}
+	}
+	return false
+}
+
 // loadFormatXL - loads format.json from disk.
 func loadFormatXL(disk StorageAPI) (format *formatXLV3, err error) {
 	buf, err := disk.ReadAll(minioMetaBucket, formatConfigFile)
@@ -391,9 +407,7 @@ func loadFormatXL(disk StorageAPI) (format *formatXLV3, err error) {
 			if err != nil {
 				return nil, err
 			}
-			if len(vols) > 1 || (len(vols) == 1 &&
-				vols[0].Name != minioMetaBucket &&
-				vols[0].Name != "lost+found") {
+			if len(vols) > 1 || (len(vols) == 1 && !isIgnoreHiddenDirectories(vols[0].Name)) {
 				// 'format.json' not found, but we
 				// found user data.
 				return nil, errCorruptedFormat