prefsstore: Fix the broken path access for the prefs

This walks through the parent paths and tries to `mkdir` on them in
turn if they don't exist.

Closes: #30

Author: jtgans

g13gui/model/prefsstore.py

@@ -1,6 +1,8 @@
 import json
 import threading
 
+from pathlib import Path
+
 from g13gui.model.prefs import Preferences
 from g13gui.common import PROFILES_CONFIG_PATH
 
@@ -23,6 +25,13 @@ def storePrefs(prefs):
         with PreferencesStore.SaveLock:
             prefsDict = prefs.saveToDict()
 
+            # make each directory in turn
+            partialpath = Path()
+            for part in PROFILES_CONFIG_PATH.parent.parts:
+                partialpath = partialpath / part
+                if not partialpath.exists():
+                    partialpath.mkdir()
+
             with open(PROFILES_CONFIG_PATH, 'w') as f:
                 f.write(json.dumps(prefsDict, default=str))
                 f.flush()