[PATCH] Client: Enhancements for xml_utils & unittest

* Added abstract base classes
    * TempXMLFile - Temporary file that unlinks on destruction
    * XMLBackup - Backup temporary file of some source content
    * XMLBase - ElementTree from Backup temporary file of source content
* Added unittests for all classes & methods

Signed-off-by: Chris Evich <cevich <at> redhat.com>
---
 client/shared/xml_utils.py          |  147 ++++++++++++++++++++++++
 client/shared/xml_utils_unittest.py |  213 ++++++++++++++++++++++++++++++++++-
 2 files changed, 358 insertions(+), 2 deletions(-)

diff --git a/client/shared/xml_utils.py b/client/shared/xml_utils.py
index d4bae45..cdfef25 100644
--- a/client/shared/xml_utils.py
+++ b/client/shared/xml_utils.py
 <at>  <at>  -3,9 +3,156  <at>  <at> 
     in python 2.4 systems.
 """

+import os.path, shutil, tempfile
+
 try:
     import autotest.common as common
 except ImportError:
     import common

+import logging
+
 from autotest.client.shared import ElementTree