Fix wrong docstring

Fields must be the final elements in an epytext string.
Signed-off-by: Michele Tartara <mtartara@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

lib/hypervisor/hv_xen.py

@@ -523,13 +523,13 @@ class XenHypervisor(hv_base.BaseHypervisor):
   def _ShutdownInstance(self, name):
     """Shutdown an instance if the instance is running.
 
-    @type name: string
-    @param name: name of the instance to stop
-
     The '-w' flag waits for shutdown to complete which avoids the need
     to poll in the case where we want to destroy the domain
     immediately after shutdown.
 
+    @type name: string
+    @param name: name of the instance to stop
+
     """
     instance_info = self.GetInstanceInfo(name)