Repeating events in December will break when upgrading from 6.1 to 6.2

• Type: Regression Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.0.0 M4
• Fix Version/s: 6.2.X EE, 7.0.0 M4
• Component/s: Calendar, Calendar > Upgrade
• Labels: None
• Branch Version/s:
  6.2.x
• Backported to Branch:
  Committed
• Story Points: 9
• Git Pull Request: https://github.com/brianchandotcom/liferay-plugins/pull/4104

Steps to Reproduce
1. In 6.1, create a calendar event
2. Set the date on December 31, and set it to repeat yearly on December 31st.
3. Upgrade to 6.2
4. You should see an error like this:
java.text.ParseException: cannot parse [[13]] in [RRULE, recur, BYMONTH, bymolist]