improve carousel demo for height change, ref #1002
improve carousel demo for height change, ref #1002

bccsafe/ant-design-mobile,bccsafe/ant-design-mobile,ant-design/ant-design-mobile,bccsafe/ant-design-mobile,bccsafe/ant-design-mobile,ant-design/ant-design-mobile,ant-design/ant-design-mobile,ant-design/ant-design-mobile,bccsafe/ant-design-mobile