Make check fails on a permissions error to nonexistent config file

[nekohayo]

Since I've been running the flatpak version for stable, my config files for GTG are not in the main XDG config folder, and apparently this causes the test suite to fail when launching make check in the git version:

_________ ERROR collecting tests/core/test_versioning.py _________
tests/core/test_versioning.py:21: in <module>
GTG/gtk/browser/adaptive_button.py:44:30 undefined name 'ChildItem'
GTG/gtk/browser/adaptive_button.py:47:39 undefined name 'ChildItem'
    from GTG.core import versioning
GTG/core/versioning.py:29: in <module>
    from GTG.core import datastore
GTG/core/datastore.py:43: in <module>
    class DataStore():
GTG/core/datastore.py:52: in DataStore
    def __init__(self, global_conf=CoreConfig()):
GTG/core/config.py:193: in __init__
    self._task_conf = open_config_file(self._task_conf_path)
GTG/core/config.py:81: in open_config_file
    open(config_file, "w").close()
E   PermissionError: [Errno 13] Permission denied: '/home/user/.config/gtg/tasks.conf'

[diegogangl]

If I recall correctly the DS in the new core doesn't auto-open the config file, so this shouldn't be a problem