contract/contract_discount/views/contract_view.xml

<?xml version="1.0"?>
<openerp>
    <data>

        <record id="account_analytic_account_form_extension_form" model="ir.ui.view">
            <field name="name">account.analytic.account.invoice.form.extension.form
            </field>
            <field name="model">account.analytic.account</field>
            <field name="inherit_id"
                ref="account_analytic_analysis.account_analytic_account_form_form" />
            <field name="arch" type="xml">
                <xpath expr="//field[@name='price_unit']" position="after">
                    <field name="discount" groups="sale.group_discount_per_so_line" />
                </xpath>
            </field>
        </record>

    </data>
</openerp>