[FIX] Fix warnings when installing hr_expense_line_supplier with demo data

[Ehtaga]

Installing hr_expense_line_supplier with demo data (for example in runbot) caused this warning:

2015-09-05 16:15:46,077 5535 WARNING 3114532-61-4f6da3-all openerp.osv.orm: WARNING: unable to set column partner_id of table hr_expense_line not null ! Try to re-run: openerp-server --update=module If it doesn't work, update records and execute manually: ALTER TABLE hr_expense_line ALTER COLUMN partner_id SET NOT NULL

I added partner_id fields on existing demo data. I had to separate the module in 2:

• the first one which creates the partner_id field in the model and adds it to the demo data
• the second one which sets the partner_id field required in the model. This one is installed automatically after the first one. As the demo expense lines already have a partner_id, this doesn't raise warning anymore.

This should avoid #61 runbot build fail for example.

[ehdem]

:+1:

[ghost]

:+1: