[FIX] web_calendar: Calendar date format incorrect

Steps to reproduce the bug:
- Set a language on your user
- Change the date format in this language and set '%d/%m/%y' (two digit year)
- Open the calendar and select day or week view

Bug:
- The date displayed on the column headings has 'y' where it should have the year.

To check the right date format: http://fullcalendar.io/docs1/utilities/formatDate/

opw:185924

addons/web_calendar/static/src/js/web_calendar.js

@@ -33,7 +33,7 @@ function get_fc_defaultOptions() {
 
     // adapt format for fullcalendar v1.
     // see http://fullcalendar.io/docs1/utilities/formatDate/
-    var conversions = [['YYYY', 'yyyy'], ['YY', 'y'], ['DDDD', 'dddd'], ['DD', 'dd']];
+    var conversions = [['YYYY', 'yyyy'], ['YY', 'yy'], ['DDDD', 'dddd'], ['DD', 'dd']];
     _.each(conversions, function(conv) {
         dateFormat = dateFormat.replace(conv[0], conv[1]);
     });