ERP5: fix an "Ambiguous name" warning for SQLMethod

The warning is:
```
Ambiguous name for method of Products.ERP5.Document.SQLMethod.SQLMethod: 'manage_main' != 'manage'
```

It happens when components are reloaded

product/ERP5/Document/SQLMethod.py

@@ -77,6 +77,7 @@ class SQLMethod(XMLObject, ZSQL, ExpressionMixin):
 
   # Override manage and manage_main with ZSQL manage and manage_main respectively
   manage = manage_main = ZSQL.manage
+  manage_main._setName('manage_main')
 
   # View content list, Force /view, Standard option in SQLMethod
   manage_options = ({'icon':'', 'label':'View','action':'view'},) \