Fix Flow 0.28 errors with parameterized types

Author: STRML

lib/Draggable.es6

@@ -21,7 +21,7 @@ type DraggableState = {
 type ConstructorProps = {
   position: { x: number, y: number },
   defaultPosition: { x: number, y: number }
-}
+};
 
 //
 // Define <Draggable>
@@ -288,7 +288,7 @@ export default class Draggable extends React.Component {
     this.setState(newState);
   };
 
-  render(): React.Element {
+  render(): React.Element<any> {
     let style = {}, svgTransform = null;
 
     // If this is controlled, we don't want to move it - unless it's dragging.

lib/DraggableCore.es6

@@ -334,7 +334,7 @@ export default class DraggableCore extends React.Component {
     return this.handleDragStop(e);
   };
 
-  render(): React.Element {
+  render(): React.Element<any> {
     // Reuse the child provided
     // This makes it flexible to use whatever element is wanted (div, ul, etc)
     return React.cloneElement(React.Children.only(this.props.children), {