When a month contains a DST change, the times in the links generated in the calendar block do not correspond with midnight, they're off by an hour.

Thus when an event is scheduled at midnight, but the link generated is for 1am (by mistake due to this bug), when following the link, the day view of the calendar claims there's no events.

Expected Outcome:
Clicking on the link to the day view of the calendar, from the month list in the calendar block, a list of activities due on that day are displayed.

Actual Outcome:
Clicking on the link to the day view of the calendar, from the month list in the calendar block, results in a 'There are no events on this day' message.

Steps to Replicate:
1. Create a course
2. Create an assignment, set due date to tomorrow
3. Add calendar block to topic
4. Click on month name in block to access monthly view
5. Hover over the day in the calendar
6. Click the link for the assignment due tomorrow to go to the day view
7. The day view appears empty. The message message 'There are no events on this day' is displayed.