store gui last wallet separately, to fix command line

gui/qt/__init__.py

@@ -149,6 +149,9 @@ class ElectrumGui:
 
     def main(self, url):
 
+        if self.config.get('wallet_path') is None and self.config.get('gui_last_wallet'):
+            self.config.read_only_options['wallet_path'] = self.config.get('gui_last_wallet')
+
         storage = WalletStorage(self.config)
         if storage.file_exists:
             try:

gui/qt/main_window.py

@@ -298,7 +298,7 @@ class ElectrumWindow(QMainWindow):
         self.load_wallet(wallet)
         self.show()
         # save path
-        self.config.set_key('default_wallet_path', filename)
+        self.config.set_key('gui_last_wallet', filename)