Remove relayoutOnUpdate prop on gemini-scrollbar

The latest gemini-scrollbar makes relayoutOnUpdate redundant, so update to it
and remove the properties.

src/components/structures/UserSettings.js

@@ -463,7 +463,6 @@ module.exports = React.createClass({
                 <SimpleRoomHeader title="Settings" onCancelClick={ this.props.onClose }/>
 
                 <GeminiScrollbar className="mx_UserSettings_body"
-                                 relayoutOnUpdate={false}
                                  autoshow={true}>
 
                 <h3>Profile</h3>