view_account_asset_asset.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>
        <record id="view_account_asset_asset_inherit" model="ir.ui.view">
            <field name="name">view.account.asset.asset.inherit</field>
            <field name="model">account.asset.asset</field>
            <field name="inherit_id" ref="account_asset.view_account_asset_asset_form"/>
            <field name="arch" type="xml">
                <xpath expr="//field[@name='salvage_value']"
                       position="replace">
                    <field name="salvage_value" string="Salvage Value" widget="monetary" options="{'currency_field': 'currency_id'}" attrs="{'invisible': [('type','=','sale')]}"/>
                </xpath>
            </field>
        </record>
    </data>
</openerp>