ilm: Remove a 'null' version if not latest (#10494)

If the ILM document requires removing noncurrent versions, the 
the server should be able to remove 'null' versions as well. 
'null' versions are created when versioning is not enabled 
or suspended.

cmd/erasure-metadata.go

@@ -103,11 +103,17 @@ func (fi FileInfo) ToObjectInfo(bucket, object string) ObjectInfo {
 			IsDir:  true,
 		}
 	}
+
+	versionID := fi.VersionID
+	if globalBucketVersioningSys.Enabled(bucket) && versionID == "" {
+		versionID = nullVersionID
+	}
+
 	objInfo := ObjectInfo{
 		IsDir:           false,
 		Bucket:          bucket,
 		Name:            object,
-		VersionID:       fi.VersionID,
+		VersionID:       versionID,
 		IsLatest:        fi.IsLatest,
 		DeleteMarker:    fi.Deleted,
 		Size:            fi.Size,