Fix missing prop and invalid propType.

Author: timmyc

client/my-sites/stats/stats-tabs/index.jsx

@@ -14,7 +14,7 @@ export default React.createClass( {
 
 	propTypes: {
 		activeKey: PropTypes.string,
-		activeIndex: PropTypes.number,
+		activeIndex: PropTypes.string,
 		dataList: PropTypes.object,
 		selectedTab: PropTypes.string,
 		switchTab: PropTypes.func,

client/my-sites/stats/stats-tabs/tab.jsx

@@ -15,6 +15,7 @@ export default React.createClass( {
 	propTypes: {
 		className: PropTypes.string,
 		gridicon: PropTypes.string,
+		href: PropTypes.string,
 		label: PropTypes.string,
 		loading: PropTypes.bool,
 		selected: PropTypes.bool,