Fix group/host var loading relative to playbook basedir

lib/ansible/executor/playbook_executor.py

@@ -73,6 +73,7 @@ class PlaybookExecutor:
         try:
             for playbook_path in self._playbooks:
                 pb = Playbook.load(playbook_path, variable_manager=self._variable_manager, loader=self._loader)
+                self._inventory.set_playbook_basedir(os.path.dirname(playbook_path))
 
                 if self._tqm is None: # we are doing a listing
                     entry = {'playbook': playbook_path}