remove unnecessary h() from diff filename (#12641)

On Rails3, escaping is default.

git-svn-id: https://svn.redmine.org/redmine/trunk@11544 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/views/common/_diff.html.erb

@@ -10,7 +10,7 @@
 <thead>
 <tr>
   <th colspan="4" class="filename">
-    <%= h(Redmine::CodesetUtil.to_utf8_by_setting(table_file.file_name)) %>
+    <%= Redmine::CodesetUtil.to_utf8_by_setting(table_file.file_name) %>
   </th>
 </tr>
 </thead>
@@ -40,7 +40,7 @@
 <thead>
   <tr>
     <th colspan="3" class="filename">
-      <%= h(Redmine::CodesetUtil.to_utf8_by_setting(table_file.file_name)) %>
+      <%= Redmine::CodesetUtil.to_utf8_by_setting(table_file.file_name) %>
     </th>
   </tr>
 </thead>