fix: tooltip throws exception in some cases #1519

Author: tangjinzhou

components/tooltip/Tooltip.jsx

@@ -82,7 +82,10 @@ export default {
         (isAntBtn &&
           (ele.componentOptions.propsData.disabled ||
             ele.componentOptions.propsData.disabled === '')) ||
-        (ele.tag === 'button' && ele.data && ele.data.attrs.disabled !== false)
+        (ele.tag === 'button' &&
+          ele.data &&
+          ele.data.attrs &&
+          ele.data.attrs.disabled !== undefined)
       ) {
         // Pick some layout related style properties up to span
         // Prevent layout bugs like https://github.com/ant-design/ant-design/issues/5254