[FIX] util/orm.py: Restore compatibility with 7.0

When the module `runsanitizer` is loaded, Odoo is trying to import `env()`
from util/orm.py. There is a check to ensure that `openerp.fields`, which
was introduced in 8.0, is not being read by earlier versions and set to None
instead.

While parsing orm.py however, all decorators are evaluated including
`no_selection_cache_validation()`, which assumes that `openerp.fields` has
been imported, and fails on an AttributeError. A check at the top of the
decorator fixes that (it was already anticipated that the decorated function
`recompute_fields` would not work in 7.0).

Part-of: #7

Author: elre-odoo

src/util/orm.py

@@ -196,6 +196,8 @@ def invalidate(records, *args):
 
 
 def no_selection_cache_validation(f=None):
+    if not version_gte("8.0"):
+        return f
     old_convert = ofields.Selection.convert_to_cache
 
     def _convert(self, value, record, validate=True):