Fix for RemoteFile and unittest.

(1).Change uuid to tempfile to build a unique filename.
(2).Add a __del__ method for unittest class to remove remote_file.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>

Fix indenting error in remote.py.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>