Fix the default for the is_a_template flag.

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

tools/python/xen/xend/XendConfig.py

@@ -298,7 +298,7 @@ class XendConfig(dict):
             'actions_after_reboot': 'restart',
             'actions_after_crash': 'restart',
             'actions_after_suspend': '',
-            'is_template': False,
+            'is_a_template': False,
             'is_control_domain': False,
             'features': '',
             'PV_bootloader': '',