Added close button

public/app/features/dashboard/partials/metadata.html

@@ -3,6 +3,9 @@
 		<i class="fa fa-info"></i>
 		Metadata
 	</div>
+  <button class="gf-box-header-close-btn" ng-click="dismiss();">
+    <i class="fa fa-remove"></i>
+  </button>
 </div>
 
 <div class="gf-box-body" style="padding-bottom: 50px;">