xend: Remove warning message from xend.log

When I created a domain, I saw the following warning message in
xend.log.  This patch removes the message from xend.log.

[2010-03-16 19:04:16 3623] WARNING (XendConfig:872) Unconverted key:
Description

Signed-off-by: Masaki Kanno <kanno.masaki@jp.fujitsu.com>

tools/python/xen/xend/XendConfig.py

@@ -233,6 +233,7 @@ XENAPI_CFG_TYPES = {
     's3_integrity' : int,
     'superpages' : int,
     'memory_sharing': int,
+    'Description': str,
 }
 
 # List of legacy configuration keys that have no equivalent in the