[Multi company][7.0] Bank statement line product_id onchange method gives wrong value

[Kinner Vachhani]

Hi,

[pre-requisite]
* Install multi company module
* Install account module

[Reproduce Bug]
* Create a user with all accounting rights and set company A as its main company
* Create a partner xyx with different payable and receivable accounts for different companies
* Create a bank statement for company B
* Select partner and observe account field
* Account field should set automatically payable/receivable account based on partner and type selected

A quick look in code reveals that context is not passed to onchange method and property always by default browse logged in user default company if no context is passed.