re-implement pickValidInfo dataDir, move to quorum calculation (#13681)

dataDir loosely based on maxima is incorrect and does not
work in all situations such as disks in the following order

- xl.json migration to xl.meta there may be partial xl.json's
  leftover if some disks are not yet connected when the disk
  is yet to come up, since xl.json mtime and xl.meta is
  same the dataDir maxima doesn't work properly leading to
  quorum issues.

- its also possible that XLV1 might be true among the disks
  available, make sure to keep FileInfo based on common quorum
  and skip unexpected disks with the older data format.

Also, this PR tests upgrade from older to a newer release if the 
data is readable and matches the checksum.

NOTE: this is just initial work we can build on top of this to do further tests.

cmd/erasure-healing.go

@@ -294,15 +294,7 @@ func (er erasureObjects) healObject(ctx context.Context, bucket string, object s
 
 	// List of disks having latest version of the object er.meta
 	// (by modtime).
-	_, modTime, dataDir := listOnlineDisks(storageDisks, partsMetadata, errs)
-
-	// make sure all parts metadata dataDir is same as returned by listOnlineDisks()
-	// the reason is its possible that some of the disks might have stale data, for those
-	// we simply override them with maximally occurring 'dataDir' - this ensures that
-	// disksWithAllParts() verifies same dataDir across all drives.
-	for i := range partsMetadata {
-		partsMetadata[i].DataDir = dataDir
-	}
+	_, modTime := listOnlineDisks(storageDisks, partsMetadata, errs)
 
 	// List of disks having all parts as per latest metadata.
 	// NOTE: do not pass in latestDisks to diskWithAllParts since
@@ -318,7 +310,7 @@ func (er erasureObjects) healObject(ctx context.Context, bucket string, object s
 
 	// Latest FileInfo for reference. If a valid metadata is not
 	// present, it is as good as object not found.
-	latestMeta, err := pickValidFileInfo(ctx, partsMetadata, modTime, dataDir, result.DataBlocks)
+	latestMeta, err := pickValidFileInfo(ctx, partsMetadata, modTime, result.DataBlocks)
 	if err != nil {
 		return result, toObjectErr(err, bucket, object, versionID)
 	}
@@ -551,6 +543,7 @@ func (er erasureObjects) healObject(ctx context.Context, bucket string, object s
 		if disk == OfflineDisk {
 			continue
 		}
+
 		// record the index of the updated disks
 		partsMetadata[i].Erasure.Index = i + 1