Clicking on calendar icon throw javascript error if the user language/locale is not supported by calendar.

Steps:
1. Install JIRA on a system with locale not supported by JIRA.
2. Login to JIRA. Click on "Create Issue" link.
3. Click on "Calendar" icon in create issue form.

Result:
1. user get an alert message "JIRA Calendar doesn't support your language". Click ok.
2. User get a javascript error "Line: 1
Error: 'this.table.style' is null or not an object"