converge listBuckets() as a peer call (#16346)

cmd/erasure-healing.go

@@ -235,6 +235,10 @@ func listAllBuckets(ctx context.Context, storageDisks []StorageAPI, healBuckets
 				// we ignore disk not found errors
 				return nil
 			}
+			if storageDisks[index].Healing() != nil {
+				// we ignore disks under healing
+				return nil
+			}
 			volsInfo, err := storageDisks[index].ListVols(ctx)
 			if err != nil {
 				return err