better logic for all-group variables for implicit localhost

lib/ansible/inventory/__init__.py

@@ -324,6 +324,7 @@ def _create_implicit_localhost(self, pattern):
         if ungrouped is None:
             self.add_group(Group('ungrouped'))
             ungrouped = self.get_group('ungrouped')
+            self.get_group('all').add_child_group(ungrouped)
         ungrouped.add_host(new_host)
         return new_host
 
@@ -452,10 +453,6 @@ def _get_host_variables(self, hostname, vault_password=None):
 
         vars = {}
 
-        # special case for ungrouped hosts, make sure group_vars/all is loaded
-        if len(host.groups) == 1 and host.groups[0].name == 'ungrouped':
-            vars = self.get_group_variables('all', vault_password=self._vault_password)
-
         # plugin.run retrieves all vars (also from groups) for host
         vars_results = [ plugin.run(host, vault_password=vault_password) for plugin in self._vars_plugins if hasattr(plugin, 'run')]
         for updated in vars_results: