re-try if init zvm driver failed

In current implementation, if get host status failed when init
zvm driver, will ignore the error, then leave nova-compute server
active but not in effect.

In zvm driver, it is required to get host status especially hcp
info, otherwise zvm driver will not work.

In this change, if get host status failed, will keeping re-try
until correctly get host status.

Change-Id: Ib04f095330fc0ae5fa8cc2a9634bf4cf660d671b

nova/tests/unit/virt/zvm/test_zvm.py

@@ -212,6 +212,7 @@ class ZVMDriverTestCases(ZVMTestCase):
             'root_gb', 'ephemeral_gb')
     _fake_inst = {'name': 'os000001'}
     _old_inst = {'name': 'rszos000001'}
+
     for k in keys:
         _fake_inst[k] = ''
         _old_inst[k] = ''
@@ -239,10 +240,6 @@ class ZVMDriverTestCases(ZVMTestCase):
                           "fakenode: FAKEDP Free: 38842.7 G\n"]
         return self._generate_xcat_resp(fake_disk_info)
 
-    def _set_fake_host_info(self):
-        self._set_fake_xcat_responses([self._fake_host_rinv_info(),
-            self._fake_disk_info(), self._gen_resp(info=['userid=fakehcp'])])
-
     def _setup_fake_inst_obj(self):
         keys = ('image_ref', 'uuid', 'user_id', 'project_id',
             'power_state', 'system_metadata', 'memory_mb', 'vcpus',
@@ -255,9 +252,28 @@ class ZVMDriverTestCases(ZVMTestCase):
 
     def setUp(self):
         super(ZVMDriverTestCases, self).setUp()
-        self._set_fake_host_info()
         self._setup_fake_inst_obj()
-        self.driver = driver.ZVMDriver(fake.FakeVirtAPI())
+        with mock.patch.object(driver.ZVMDriver, 'update_host_status') as uhs:
+            uhs.return_value = [{
+                'host': 'fakehost',
+                'allowed_vm_type': 'zLinux',
+                'vcpus': 10,
+                'vcpus_used': 10,
+                'cpu_info': {'Architecture': 's390x', 'CEC model': '2097'},
+                'disk_total': 406105,
+                'disk_used': 367263,
+                'disk_available': 38842,
+                'host_memory_total': 16384,
+                'host_memory_free': 8096,
+                'hypervisor_type': 'zvm',
+                'hypervisor_version': '630',
+                'hypervisor_hostname': 'fakenode',
+                'supported_instances': [('s390x', 'zvm', 'hvm')],
+                'zhcp': {'hostname': 'fakehcp.fake.com',
+                         'nodename': 'fakehcp', 'userid': 'fakehcp'},
+                'ipl_time': 'IPL at 03/13/14 21:43:12 EDT',
+            }]
+            self.driver = driver.ZVMDriver(fake.FakeVirtAPI())
         self.mox.UnsetStubs()
 
     def test_init_driver(self):