Ensure trace enabled=false in Release config (#6998)

Author: xavierdecoster

src/NuGetGallery/Web.Release.config

@@ -16,6 +16,11 @@
   -->
   <system.web>
     <compilation xdt:Transform="RemoveAttributes(debug)" />
+    
+    <!-- This is set to 'false' for security reasons. -->
+    <trace xdt:Transform="Remove"/>
+    <trace xdt:Transform="InsertAfter(/configuration/system.web/compilation)" enabled="false"/>
+    
     <!--
       In the example below, the "Replace" transform will replace the entire 
       <customErrors> section of your web.config file.