Set fetch_cluster flag to False when _inner_load_cluster called

Set the same flag to True if the cluster does not yet exists in
ZooKeeper

patroni/zookeeper.py

@@ -132,8 +132,11 @@ class ZooKeeper(AbstractDCS):
         return members
 
     def _inner_load_cluster(self):
+        self.fetch_cluster = False
         self.event.clear()
         nodes = set(self.get_children(self.client_path(''), self.cluster_watcher))
+        if not nodes:
+            self.fetch_cluster = True
 
         # get initialize flag
         initialize = self._INITIALIZE in nodes

tests/test_zookeeper.py

@@ -46,7 +46,7 @@ class MockKazooClient(Mock):
     def get_children(self, path, watch=None, include_data=False):
         if not isinstance(path, six.string_types):
             raise TypeError("Invalid type for 'path' (string expected)")
-        if path == '/no_node':
+        if path.startswith('/no_node'):
             raise NoNodeError
         elif path in ['/service/bla/', '/service/test/']:
             return ['initialize', 'leader', 'members', 'optime', 'failover']
@@ -121,6 +121,8 @@ class TestZooKeeper(unittest.TestCase):
     def test__inner_load_cluster(self):
         self.zk._base_path = self.zk._base_path.replace('test', 'bla')
         self.zk._inner_load_cluster()
+        self.zk._base_path = self.zk._base_path = '/no_node'
+        self.zk._inner_load_cluster()
 
     def test_get_cluster(self):
         self.assertRaises(ZooKeeperError, self.zk.get_cluster)