title: Field invisible based on parent field Odoo 8
body: <p>I need to invisible a column of one2many field based on parent field.
  By inheriting account.invoice model i have added a field inv_type. In account_invoice_line i need to make invisible field 'quantity' if inv_type = 'utility'.</p>
  
  <p>I tried below code:</p>
  
  <p>xml:</p>
  
  <pre><code>&lt;record id="ams_invoice_form" model="ir.ui.view"&gt;
          &lt;field name="name"&gt;account.invoice.form&lt;/field&gt;
          &lt;field name="model"&gt;account.invoice&lt;/field&gt;
          &lt;field name="inherit_id" ref="account.invoice_form"&gt;&lt;/field&gt;
          &lt;field name="inherit_id" ref="ams.3e_invoice_form"&gt;&lt;/field&gt;
          &lt;field name="arch" type="xml"&gt;
              &lt;xpath expr="//notebook/page/field/tree/field[@name='quantity']" position="replace"&gt;
                  &lt;field name="quantity"  attrs="{'invisible':[('parent.inv_type,'=','utility')]}" /&gt;
                  &lt;field name="consumed_unit"/&gt;
                  &lt;field name="fixed_charge"/&gt;
              &lt;/xpath&gt;
  
          &lt;/field&gt;
      &lt;/record&gt;
  </code></pre>
  
  <p>It throwing an client error:</p>
  
  <pre><code> Odoo Client Error
  
   Error: Unknown field parent.invoice_type in domain [["parent.invoice_type","=","utility"]]
  </code></pre>
  
  <p>Please suggest a solution.. thanks..</p>