fs-v1: Remove unused property

(cherry picked from commit 9137a44)

cmd/fs-v1.go

@@ -76,7 +76,6 @@ type FSObjects struct {
 // Represents the background append file.
 type fsAppendFile struct {
 	sync.Mutex
-	parts    []int  // List of parts appended.
 	filePath string // Absolute path of the file in the temp location.
 }