Impacted versions:
9.0 Community & 9.0 Enterprise

Steps to reproduce:
- Open up a V9 Enteprise Runbot
- Go to projects and open up the issues for the project 'Data Import/Export Plugin'
- Click on 'Create' to create a new issue. You will see the following form:
  ![image](https://cloud.githubusercontent.com/assets/6352350/13873556/8f826fbc-ecf2-11e5-95aa-e5cd7965b976.png)
  Notice how the Contact is filled in with the name 'Delta PC' and that no e-mail is filled in. When you open up this contact its form you will see he has an e-mail filled in:
  ![image](https://cloud.githubusercontent.com/assets/6352350/13873580/afd81f0a-ecf2-11e5-960f-91e14a999578.png)
- Remove the contact on the issue, click somewhere else and now fill in the contact again. The moment you add the contact again the onchange function goes off and the e-mail is filled in automatically:
  ![image](https://cloud.githubusercontent.com/assets/6352350/13873605/d0884068-ecf2-11e5-8892-5fcd0fc692b2.png)

Current behavior:
When clicking on 'Create' for creating a new issue on a project the customer its e-mail is not automatically filled in because the onchange does not seem to have an effect on the record.

Expected behavior:
When click on 'Create' for creating a new issue on a project the customer his e-mail is filled in automatically (provided there is one).

addons/project_issue/project_issue.py
project_id = self._get_default_project_id(cr, uid, context)
        if project_id:
            project = self.pool.get('project.project').browse(cr, uid, project_id, context=context)
            if project and project.partner_id:
                return project.partner_id.id
        return False
    def _get_default_project_id(self, cr, uid, context=None):
        """ Gives default project by checking if present in the context """
        return self._resolve_project_id_from_context(cr, uid, context=context)
    def _get_default_stage_id(self, cr, uid, context=None):
        """ Gives default stage_id """
        project_id = self._get_default_project_id(cr, uid, context=context)
        return self.stage_find(cr, uid, [], project_id, [('fold', '=', False)], context=context)
    def _resolve_project_id_from_context(self, cr, uid, context=None):