erp5_trade: Proxify my_ledger to Base_viewTradeFieldLibrary as it should have...

erp5_trade: Proxify my_ledger to Base_viewTradeFieldLibrary as it should have always been (06f701a4).

This fixes TestXHTML.test_configurationOfFieldLirary Unit Test failure:
  Assertionerror: 1 fields to modify
  erp5_trade/TradeModelPath_view/my_ledger: Unproxify Field

bt5/erp5_trade/SkinTemplateItem/portal_skins/erp5_trade/TradeModelPath_view/my_ledger.xml

@@ -69,7 +69,7 @@
                 </item>
                 <item>
                     <key> <string>form_id</string> </key>
-                    <value> <string>Base_viewPDMFieldLibrary</string> </value>
+                    <value> <string>Base_viewTradeFieldLibrary</string> </value>
                 </item>
                 <item>
                     <key> <string>title</string> </key>