Accounts: Fix pylint errors

gajim/data/gui/remove_account_window.ui

@@ -7,7 +7,7 @@
     <property name="border_width">18</property>
     <property name="resizable">False</property>
     <property name="type_hint">dialog</property>
-    <signal name="destroy" handler="on_remove_account_window_destroy" swapped="no"/>
+    <signal name="destroy" handler="_on_destroy" swapped="no"/>
     <child>
       <placeholder/>
     </child>

gajim/gtk/accounts.py

@@ -627,7 +627,7 @@ def connect_signal(self, stack):
         return stack.connect('notify::visible-child',
                              self._on_visible_child_changed)
 
-    def _on_visible_child_changed(self, stack, param):
+    def _on_visible_child_changed(self, stack, _param):
         if self == stack.get_visible_child():
             self.listbox.update_states()
 
@@ -917,7 +917,7 @@ class RemoveAccountWindow:
     then remove the account given
     """
 
-    def on_remove_account_window_destroy(self, _widget):
+    def _on_destroy(self, _widget):
         if self.account in app.interface.instances:
             del app.interface.instances[self.account]['remove_account']
 
@@ -941,7 +941,8 @@ def remove():
             not self._ui.remove_and_unregister_radiobutton.get_active():
                 # change status to offline only if we will not
                 # remove this JID from server
-                app.connections[self.account].change_status('offline', 'offline')
+                app.connections[self.account].change_status('offline',
+                                                            'offline')
             if self._ui.remove_and_unregister_radiobutton.get_active():
                 if not self.account in app.connections:
                     ErrorDialog(