css: remove the annoying tr:hover rule for diffstat

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

cgit.css

@@ -272,10 +272,6 @@ table.diffstat {
 	background-color: #eee;
 }
 
-table.diffstat tr:hover {
-	background-color: #ccc;
-}
-
 table.diffstat th {
 	font-weight: normal;
 	text-align: left;