Fix reference to HttpXendClientProtocol. This was previously referring to the

abstract base class, which was never going to work.  (This is debugging code
only, so I presume that no-one has used it for a long time, but it's doing no
harm hanging around.)

Signed-off-by: Ewan Mellor <ewan@xensource.com>

tools/python/xen/xend/XendClient.py

@@ -354,7 +354,7 @@ class Xend:
 def getHttpServer(srv=None):
     """Create and return a xend client.
     """
-    return Xend(srv=srv, client=XendClientProtocol())
+    return Xend(srv=srv, client=HttpXendClientProtocol())
 
 def getUnixServer(srv=None):
     """Create and return a unix-domain xend client.