coldcard: small fixes

electrum/gui/qt/wallet_info_dialog.py

@@ -162,6 +162,9 @@ class WalletInfoDialog(WindowModalDialog):
 
         vbox.addStretch(1)
         btn_export_info = run_hook('wallet_info_buttons', window, self)
+        if btn_export_info is None:
+            btn_export_info = []
+
         btn_close = CloseButton(self)
         btns = Buttons(*btn_export_info, btn_close)
         vbox.addLayout(btns)

electrum/plugins/coldcard/qt.py

@@ -29,8 +29,7 @@ class Plugin(ColdcardPlugin, QtPluginBase):
     def create_handler(self, window):
         return Coldcard_Handler(window)
 
-    @staticmethod
-    def trim_file_suffix(path):
+    def trim_file_suffix(self, path):
         return path.rsplit('.', 1)[0]
 
     @only_hook_if_libraries_available