Adding tooltip to Kapacitor Rule save button

ui/src/kapacitor/components/RuleHeader.js

@@ -1,4 +1,5 @@
 import React, {PropTypes} from 'react';
+import ReactTooltip from 'react-tooltip';
 
 export const RuleHeader = React.createClass({
   propTypes: {
@@ -64,9 +65,10 @@ export const RuleHeader = React.createClass({
 
     return (
       <div>
-        <button className="btn btn-sm btn-default disabled" title={validationError}>
+        <button className="btn btn-sm btn-default disabled" data-for="save-kapacitor-tooltip" data-tip={validationError}>
           Save Rule
         </button>
+        <ReactTooltip id="save-kapacitor-tooltip" effect="solid" html={true} offset={{top: 2}} place="bottom" class="influx-tooltip kapacitor-tooltip place-bottom" />
       </div>
     );
   },