return an empty message if table contains no data #6109 (#7487)

public/app/plugins/panel/table/module.html

@@ -1,6 +1,7 @@
+
 <div class="table-panel-container">
-	<div class="table-panel-header-bg"></div>
-	<div class="table-panel-scroll">
+        <div class="table-panel-header-bg" ng-show="ctrl.dataRaw.length>0"></div>
+	<div class="table-panel-scroll" ng-show="ctrl.dataRaw.length>0">
 		<table class="table-panel-table">
 			<thead>
 				<tr>
@@ -20,5 +21,10 @@
 		</table>
 	</div>
 </div>
+<div class="datapoints-warning" ng-show="ctrl.dataRaw.length===0">
+          <span class="small" >
+              No datapoints <tip>No datapoints returned from metric query</tip>
+          </span>
+</div>
 <div class="table-panel-footer">
 </div>