[FIX] fields: make sure fields are set up before using them

Non-setup fields could cause problems in two places:
- when traversing the chain of fields in related fields;
- when adding recomputation triggers on inverse fields

Both issues are fixed by this patch.

openerp/fields.py

@@ -447,6 +447,7 @@ class Field(object):
         for name in self.related:
             recs._setup_fields()
             field = recs._fields[name]
+            field.setup(env)
             recs = recs[name]
             fields.append(field)
 
@@ -569,6 +570,8 @@ class Field(object):
                 self.recursive = True
                 continue
 
+            field.setup(env)
+
             #_logger.debug("Add trigger on %s to recompute %s", field, self)
             field._triggers.add((self, '.'.join(path0 or ['id'])))