fix Symbol svgId undefined bug

elements/Symbol.js

@@ -16,6 +16,7 @@ class SymbolElement extends Component{
         let {props} = this;
         return <Defs.Item
             id={props.id}
+            svgId={props.svgId}
         >
             <ViewBox
                 {...props}

lib/fillFilter.js

@@ -46,7 +46,7 @@ export default function (props) {
 
         return rgba(props.fill, fillOpacity);
     } else if (props.fill === undefined) {
-        
+
         let fillOpacity = +props.fillOpacity;
         if (isNaN(fillOpacity)) {
             fillOpacity = 1;