Bug repeating monthly recurring todos
Fix failing test

As far as I can tell, this is how the test is intended to work, and how
it works in v2.2.2. If a recurring todo set to show on the date is
completed *on* the specified date, it will create a deferred one for the
*next* month.
Merge pull request #209 from iangreenleaf/monthly_recurring_bug

Fix endlessly repeating monthly recurring todos