crash when there is a "key field for updating" that is not a string

latest openerp 6.1 [server r4291, addons r7036, web r2469] with enapps-csv-import-tool r9

Hi!
To reproduce:
- create a new database with demo data
- select UK language
- install ea_import_examples
- open the "partners" import chain
- select the file "partner data.csv"
- run the import
- you get AttributeError: 'int' object has no attribute 'encode'

Tentative analysis: the problem has to do with "required for updating" fields that are not strings (eg floats or m2o). The problem seems to happen here
http://bazaar.launchpad.net/~enapps-london-uk/enapps-csv-import-tool/trunk/view/head:/ea_import/ea_import_template.py#L95
at line 95.

A possible fix could be to check there if we actually have a string and do utf8 work only in that case.

What I find surprising is that demo data is broken.

Thanks!