objectLayer: Check for format.json in a wrapped disk. (#3311)

This is needed to validate if the `format.json` indeed exists
when a fresh node is brought online.

This wrapped implementation also connects to the remote node
by attempting a re-login. Subsequently after a successful
connect `format.json` is validated as well.

Fixes #3207

cmd/naughty-disk_test.go

@@ -28,7 +28,7 @@ import (
 // Programmed errors are stored in errors field.
 type naughtyDisk struct {
 	// The real disk
-	disk *posix
+	disk *retryStorage
 	// Programmed errors: API call number => error to return
 	errors map[int]error
 	// The error to return when no error value is programmed
@@ -39,7 +39,7 @@ type naughtyDisk struct {
 	mu sync.Mutex
 }
 
-func newNaughtyDisk(d *posix, errs map[int]error, defaultErr error) *naughtyDisk {
+func newNaughtyDisk(d *retryStorage, errs map[int]error, defaultErr error) *naughtyDisk {
 	return &naughtyDisk{disk: d, errors: errs, defaultErr: defaultErr}
 }
 
@@ -47,6 +47,20 @@ func (d *naughtyDisk) String() string {
 	return d.disk.String()
 }
 
+func (d *naughtyDisk) Init() (err error) {
+	if err = d.calcError(); err != nil {
+		return err
+	}
+	return d.disk.Init()
+}
+
+func (d *naughtyDisk) Close() (err error) {
+	if err = d.calcError(); err != nil {
+		return err
+	}
+	return d.disk.Close()
+}
+
 func (d *naughtyDisk) calcError() (err error) {
 	d.mu.Lock()
 	defer d.mu.Unlock()