xend: Correctly catch invalid domain lookups

If a client asks about a non-existent domain, report the error back
properly instead of just backtracing within xend.

Signed-off-by: John Levon <john.levon@sun.com>

tools/python/xen/web/SrvDir.py

@@ -20,7 +20,7 @@ import types
 from xen.xend import sxp
 from xen.xend import PrettyPrint
 from xen.xend.Args import ArgError
-from xen.xend.XendError import XendError
+from xen.xend.XendError import XendError, XendInvalidDomain
 #from xen.xend.XendLogging import log
 
 import resource
@@ -71,6 +71,8 @@ class SrvDir(SrvBase):
             val = self.get(x)
         except XendError, ex:
             return self.noChild(str(ex))
+        except XendInvalidDomain, ex:
+            return self.noChild(str(ex))
         if val is None:
             return self.noChild('Not found: ' + str(x))
         else: