wizard: try harder to have temporarily stored pw erased from memory

electrum/base_wizard.py

@@ -582,6 +582,7 @@ class BaseWizard(Logger):
         if not self.pw_args:
             return
         password, encrypt_storage, storage_enc_version = self.pw_args
+        self.pw_args = None  # clean-up so that it can get GC-ed
         storage = WalletStorage(path)
         storage.set_keystore_encryption(bool(password))
         if encrypt_storage:

electrum/gui/qt/installwizard.py

@@ -287,7 +287,7 @@ class InstallWizard(QDialog, MessageBoxMixin, BaseWizard):
                 else:
                     raise Exception('Unexpected encryption version')
 
-        return self.temp_storage.path, (self.temp_storage if self.temp_storage.file_exists() else None)  #
+        return self.temp_storage.path, (self.temp_storage if self.temp_storage.file_exists() else None)
 
     def run_upgrades(self, storage):
         path = storage.path