[FIX] web: Y-axis formatting

In case of a line graph, the values of the Y axis are not formatted as
numbers, although they are on the bar graph.

addons/web/static/src/js/views/graph_widget.js

@@ -301,6 +301,7 @@ return Widget.extend({
         });
         chart.xAxis.tickValues(tickValues)
             .tickFormat(tickFormat);
+        chart.yAxis.tickFormat(function(d) { return openerp.web.format_value(d, { type : 'float' });});
 
         chart(svg);
         this.to_remove = chart.update;