Bugfix in graphs

bzr revid: fp@tinyerp.com-3cca4baa8ed640e88466b89f1086ca6071f28bdb

addons/sale/sale_view.xml

@@ -297,7 +297,7 @@
 		<field name="type">graph</field>
 		<field name="arch" type="xml">
 			<graph string="Sales Order Lines">
-				<field name="product_id" group="True"/>
+				<field name="product_id"/>
 				<field name="price_unit" operator="+"/>
 			</graph>
 		</field>