fix: table ssr has invaild style #231

Author: tangjinzhou

components/vc-table/src/ColGroup.jsx

@@ -34,7 +34,7 @@ export default {
         return (
           <col
             key={c.key || c.dataIndex}
-            style={{ width, minWidth: width }}
+            style={width ? { width, minWidth: width } : {}}
           />
         )
       })

components/vc-table/src/TableHeaderRow.jsx

@@ -21,7 +21,9 @@ const TableHeaderRow = {
     const rowProps = customHeaderRow(row.map(cell => cell.column), index)
     const customStyle = rowProps ? rowProps.style : {}
     const style = { height, ...customStyle }
-
+    if (style.height === null) {
+      delete style.height
+    }
     return (
       <HeaderRow {...rowProps} style={style}>
         {row.map((cell, i) => {