remove SetDiskLoc() rely on the endpoint values instead (#19475)

the disk location never changes in the lifetime of a
MinIO cluster, even if it did validate this close to the
disk instead at the higher layer.

Return appropriate errors indicating an invalid drive, so
that the drive is not recognized as part of a valid
drive.

cmd/xl-storage_test.go

@@ -23,6 +23,7 @@ import (
 	"crypto/rand"
 	"fmt"
 	"io"
+	"net/url"
 	"os"
 	slashpath "path"
 	"runtime"
@@ -114,13 +115,29 @@ func TestIsValidVolname(t *testing.T) {
 	}
 }
 
+func newLocalXLStorage(path string) (*xlStorage, error) {
+	return newLocalXLStorageWithDiskIdx(path, 0)
+}
+
+// Initialize a new storage disk.
+func newLocalXLStorageWithDiskIdx(path string, diskIdx int) (*xlStorage, error) {
+	u := url.URL{Path: path}
+	return newXLStorage(Endpoint{
+		URL:     &u,
+		IsLocal: true,
+		PoolIdx: 0,
+		SetIdx:  0,
+		DiskIdx: diskIdx,
+	}, true)
+}
+
 // creates a temp dir and sets up xlStorage layer.
 // returns xlStorage layer, temp dir path to be used for the purpose of tests.
 func newXLStorageTestSetup(tb testing.TB) (*xlStorageDiskIDCheck, string, error) {
 	diskPath := tb.TempDir()
 
 	// Initialize a new xlStorage layer.
-	storage, err := newLocalXLStorage(diskPath)
+	storage, err := newLocalXLStorageWithDiskIdx(diskPath, 3)
 	if err != nil {
 		return nil, "", err
 	}