hover effect for filter remove button

git-svn-id: https://dev.finn.de/svn/cockpit/branches/reporting_merge@2063 7926756e-e54e-46e6-9721-ed318f58905e

assets/stylesheets/reporting.css

@@ -149,6 +149,10 @@ table#filter_table td > label {
   position: absolute;
 }
 
+.icon-filter-rem:hover {
+  background-image: url(../images/remove_hover.png);
+}
+
 .filter {
   -webkit-border-radius: 5px;
   -moz-border-radius: 5px;