fix radial gradient memory leak

Example/examples/Text.js

@@ -118,29 +118,12 @@ class TextFill extends Component{
 class TextPath extends Component{
     static title = 'Draw text along path';
 
-    constructor(...args) {
-        super(...args);
-        this.state = {
-            key: 0
-        };
-    }
-
-    componentDidMount() {
-        let self = this;
-        //setInterval(function () {
-        //    self.setState({
-        //        key: self.state.key + 1
-        //    });
-        //}, 50);
-    }
-
     render() {
         return <Svg
             height="60"
             width="200"
         >
             <Text
-                key={this.state.key}
                 fill="red"
                 path={`
                     M 10 20