NFSv3: Delete duplicate judgement in nfs3_async_handle_jukebox

As eb96d5c9

 ("SUNRPC handle EKEYEXPIRED in call_refreshresult")
commit handle EKEYEXPIRED in call_refreshresult, so there is only handle
when "task->tk_status" is equal "-EJUKEBOX" in nfs3_async_handle_jukebox.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>