xl-storage: Do not stat bucket assuming the object exists (#11201)
xl-storage: Do not stat bucket assuming the object exists (#11201)

In HEAD/GET, only STAT the bucket if the 
object does not exist to return the correct
error response.

minio/minio,donatello/minio,balamurugana/minio,krisis/minio,vadmeste/minio,minio/minio,balamurugana/minio,NitishT/minio,krisis/minio,NitishT/minio,donatello/minio,NitishT/minio,NitishT/minio,vadmeste/minio