Fix admin password skip check.

Skip admin password configuration only if the agent 'version' is
empty. Previously both the 'version' and 'agent_build' were
required to be set.

As the 'agent_build' table is primarily used for upgrades
there should be no requirement that a record exist in order
to configure admin passwords.

Fixes LP Bug #925237.

Change-Id: Ie4530a30ed02f3d49a07037e9d1cc52ef0af1dd4

nova/virt/xenapi/vmops.py

@@ -501,7 +501,7 @@ def _spawn(self, instance, vm_ref):
 
         # if the guest agent is not available, configure the
         # instance, but skip the admin password configuration
-        no_agent = version is None or agent_build is None
+        no_agent = version is None
         self._configure_instance(ctx, instance, vm_ref, no_agent)
 
     def _handle_spawn_error(self, vdis, spawn_error):