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
_name = "project.issue.version"
    _order = "name desc"
    _columns = {
        'name': fields.char('Version Number', required=True),
        'active': fields.boolean('Active', required=False),
    }
    _defaults = {
        'active': 1,
    }
class project_issue(osv.Model):
    _name = "project.issue"
    _description = "Project Issue"
    _order = "priority desc, create_date desc"
    _inherit = ['mail.thread', 'ir.needaction_mixin']
    _mail_post_access = 'read'
    _track = {
        'stage_id': {
            
            'project_issue.mt_issue_new': lambda self, cr, uid, obj, ctx=None: obj.stage_id and obj.stage_id.sequence <= 1,
            'project_issue.mt_issue_stage': lambda self, cr, uid, obj, ctx=None: obj.stage_id and obj.stage_id.sequence > 1,
        },
        'user_id': {
            'project_issue.mt_issue_assigned': lambda self, cr, uid, obj, ctx=None: obj.user_id and obj.user_id.id,
        },
        'kanban_state': {
            'project_issue.mt_issue_blocked': lambda self, cr, uid, obj, ctx=None: obj.kanban_state == 'blocked',
            'project_issue.mt_issue_ready': lambda self, cr, uid, obj, ctx=None: obj.kanban_state == 'done',
        },
    }
    def _get_default_partner(self, cr, uid, context=None):