Fix double reboot issue during soft reboot

Using the ID of domain in Libvirt to recognize the hard reboot has been
implemented or not, if the ID changed, we believe the domain has been rebooted,
return True and break from soft reboot.

Fixes: bug #1046356

Change-Id: Iec2f9e8225cfe2779f84d2095667f3c0e621e935

nova/tests/fakelibvirt.py

@@ -179,6 +179,7 @@ class Domain(object):
         self._def = self._parse_definition(xml)
         self._has_saved_state = False
         self._snapshots = {}
+        self._id = self._connection._id_counter
 
     def _parse_definition(self, xml):
         try:
@@ -299,6 +300,9 @@ class Domain(object):
         self._state = VIR_DOMAIN_SHUTOFF
         self._connection._mark_not_running(self)
 
+    def ID(self):
+        return self._id
+
     def name(self):
         return self._def['name']
 
@@ -516,6 +520,8 @@ class Connection(object):
         if dom._transient:
             self._undefine(dom)
 
+        dom._id = -1
+
         for (k, v) in self._running_vms.iteritems():
             if v == dom:
                 del self._running_vms[k]