detect dangling links

gui/qt/__init__.py

@@ -181,8 +181,8 @@ class ElectrumGui:
     def main(self):
         self.timer.start()
         self.config.open_last_wallet()
-        if not self.start_new_window(self.config.get_wallet_path(),
-                                     self.config.get('url')):
+        path = self.config.get_wallet_path()
+        if not self.start_new_window(path, self.config.get('url')):
             return
 
         signal.signal(signal.SIGINT, lambda *args: self.app.quit())

lib/simple_config.py

@@ -78,6 +78,8 @@ class SimpleConfig(PrintError):
 
         # Make directory if it does not yet exist.
         if not os.path.exists(path):
+            if os.path.islink(path):
+                raise BaseException('Dangling link: ' + path)
             os.mkdir(path)
 
         print_error("electrum directory", path)