[FIX] fields: skip missing triggers for computed custom fields

This improves ddafbab3e4 by still loading the
field, but be tolerant if setting its triggers fails.

openerp/models.py

@@ -728,8 +728,6 @@ class BaseModel(object):
                 attrs['domain'] = eval(field['domain']) if field['domain'] else None
             # add compute function if given
             if field['compute']:
-                if partial and field['depends']:
-                    continue
                 attrs['compute'] = make_compute(field['compute'], field['depends'])
             self._add_field(name, Field.by_type[field['ttype']](**attrs))
 
@@ -3061,7 +3059,10 @@ class BaseModel(object):
 
         # set up field triggers
         for field in cls._fields.itervalues():
-            field.setup_triggers(self.env)
+            # dependencies of custom fields may not exist; ignore that case
+            exceptions = (Exception,) if field.manual else ()
+            with tools.ignore(*exceptions):
+                field.setup_triggers(self.env)
 
         # add invalidation triggers on model dependencies
         if cls._depends: